By George Hobica
Airfarewatchdog.com

If you're an airline, January 26, 2012 is a day that will go down in infamy. That’s the day that airlines will no longer be able to send you an email with a subject line readin "Europe sale from $169!" or place an ad in your local newspaper with a headline like "Worldwide sale from $59!"

Thanks to new U.S. D.O.T. rules, airlines will now have to include "all mandatory taxes and fees in the advertised fare." So what this means to you the consumer: instead of that $169 "come on" price to London that's really just the fare one-way, before taxes, government fees, and surcharges kick in, on a ticket that actually requires a round- trip purchase, you'll now see a price more like $900--the full round-trip fare including taxes, fuel surcharges, and government fees. (Theoretically, if a fare can be purchased just one-way you'll see the one-way price including those extras.)

And to make things even more interesting, you may see a range of tax-included fares on the same route, although how this will work is still up in the air. For instance, a nonstop flight from New York to LA will have a different tax than one connecting in Dallas or one stopping in Salt Lake City. That's because every time a plane lands and takes off, airports add their own fees, which vary from airport to airport.

Only mandatory fees will be included in ads

But you will not see all possible non-mandatory fees, such as checked bag fees, in advertised prices, and this makes sense since you might not be liable for paying these fees at all (if you're not checking bags, for instance, or have premier status in your frequent flyer program).

And while it would be great if airline and online travel agency booking sites allowed you to calculate what your final cost might be if you did check bags, imagine what that process would look like. The site would have to ask you to weigh your bag (how's that bathroom scale working these days?) since a bag weighing under 50 pounds would cost less than one weighing 52 pounds. And you'd have to tell the site whether you have an airline credit card that waives your first checked bag fee. And your frequent flyer status. Accomplishing this will keep the airlines' computer programmers busy for months.

But all airlines are now required to have a prominent link from their home pages to a page showing all their optional fees for things like checked bags and change fees.

A new 24-hour hold rule

The other major new rule taking effect, which airlines also won't like, allows consumers to put a fare and a reservation on hold for 24-hours a without paying for it. True, previously you could hold a fare for 24 hours on most airlines (except JetBlue) but you'd have to pay for it first. Why won't airlines like this? Well, now, as a consumer, I can theoretically book my New York to LA trip on 10 different airlines, holding seats that other consumers won't be able to book. Will this play havoc with the airlines' reservation systems and perhaps mess with their yield management systems (the way they adjust fares as seats on a particular flight sell out?). Possibly. It may also require them to adjust the way they overbook flights to compensate for no shows (the reason JetBlue never allowed 24-hour holds is that it doesn't intentionally overbook flights).

Why us?

While the all-in fare advertising rule is a more honest approach, ads with higher fares may discourage consumers from shopping on airline websites. And airlines make the argument that cable TV providers like Time Warner and Verizon, and cell phone carriers such as ATT Wireless, aren't required to show all the taxes and fees in their ads (that $99 per month cable bill, as we all know, really costs more like $139.50 or whatever when the monthly bill comes).

Why are you just picking on us, the airlines wonder. Why isn't Macy's required to include sales tax in their ads? How about those car dealerships? Well, guys, don't be too surprised if the F.C.C. and D.O.J. aren't watching over the D.O.T.'s shoulder.  

Every Thursday at 6:50 a.m. ET (repeated at 10.50 a.m.), Airfarewatchdog's George Hobica helps the Weather Channel's Al Roker scout out some enticing last minute travel deals for the coming weekend on Wake Up With Al.

Here's our pick of three great destinations/routes. Watch Al's show on Thursday to see what the weather will be when you arrive. And scroll down for links to the airlines' last minute weekend web pages.

Atlanta to Newark, NJ depart Sat return Mon, $220 round-trip including taxes on United, 5 suitcases via Kayak.com

Pittsburgh to Chicago depart Sat return Mon or Tue; $160 roundtrip including incl. tax on United, 5 suitcases via United.com

San Francisco to San Diego depart Sat return Mon or Tue,  $179 roundtrip incl. tax on United, 5 suitcases  via TripAdvisor.com/flights

This week's Delta last minute weekend fares

This week's US Air E-Saver weekend fares

This week's American Airlines last minute weekend fares

This week's United Airlines last minute weekend fares

It used to be all so simple, back when airfares changed so infrequently that airlines actually printed them on their schedules. You'd call your favorite travel agent to find the best deal, pack your bags and jet off. And there were only two kinds of fares: coach and first class.

Now, with airfares changing literally by the second and an alphabet soup of different offers, finding the "best" deal is a challenge. This step-by-step guide will get you ready for takeoff.

Sign up for free airfare alerts

Why do all the work hunting down a low airfare yourself when you can have someone else do it for free? Many airfare search and listing sites, such as TripAdvisor.com/flights, Travelocity.com, Hotwire.com, Bing.com/travel and, of course, Airfarewatchdog.com offer e-mail airfare alerts when prices go down. This chart compares many of the leading airfare alert sites. (By the way, only Airfarewatchdog lists fares on Southwest Airlines).

Learn about sales on Twitter

Because some of the best unadvertised airfare sales last only a few hours (even if they're good for travel over a long period), even the best-intentioned email alert can be too late. The beauty of Twitter is that it's instantaneous. Many airlines and alert sites now tweet this deals instead of emailing them.

Get e-mail from your airlines

Next: Sign up for e-mails and frequent flyer programs. Airlines are trying to woo customers to book directly with them by offering special deals when you subscribe. Sign up for emails from foreign-based airlines and from US-based carriers.

Next step: are you a flexible travel date flyer?

Doesn't really matter when you go as long as it's cheap? Some websites offer flexible date search up to 330 days ahead; others (mostly those powered by a company called ITA Software) only do searches in 30-day increments. Read more about flexible travel date searching.

These sites can be helpful if your dates are set, but you also might want to try "meta search" sites such as Kayak.com, Tripadvisor.com/Flights and Momondo.com. Warning: None of them include Southwest's fares, however, or fares on the smaller but growing Allegiant Airlines.

"Meta search" vs. online travel agency

So what's the difference? For one thing, online travel agencies such as Expedia have toll-free numbers with agents standing by to help you book or re-book a flight; meta-search sites don't. But there are many other differences.

Airline websites sometimes have the best fares

Increasingly, airlines aren't sharing their very best fares with third-party sites such as Kayak. Case in point: recent fares to London from the West Coast for $420 round-trip including tax that were only available on Spanish airline Iberia's website (similar fares were twice that elsewhere). So once you've found a fare, definitely check airline sites directly.

Watch out for promo codes

From time to time, you'll receive promo codes in your e-mail because you signed up for e-mail from your favorite airlines and online travel agencies. These codes can only be redeemed if you book directly on the airlines' websites, another way they try to cut out the middleman. (Airfarewatchdog lists any promo codes we find on the AirfarewatchBlog).

When to use your miles

Rather than cashing in 25,000 or even 50,000 miles for a domestic economy class ticket that might have cost you $250 or $300, why not splurge for a trip to Europe (50,000 miles on some airlines) that might cost many times more? Or upgrade your $400 economy class seat to a $2,800 business class fare for 30,000 miles on domestic routes? A general rule: if the economy class fare is $400 or more, spending 25,000 miles is a good deal. Less than that, you might be better offering paying cash and saving your miles.

Getting the best last-minute airfares

You'll often get the best fares if you book at least 7 to 21 days ahead of departure. Otherwise, your best bet is Priceline.com's "Name your own price" feature or Hotwire.com. Also take a look at Lastminute.com which packages last minute airfares with hotel and rental car deals -- sometimes for less than what you'd pay for airfare alone.

When to use a real live travel agent

As good as do-it-yourself online sources can be, your friendly neighborhood travel agent may have some tricks up her sleeve to save you money. Let's say, for example, that you get an airfare alert that fares from Houston to Honolulu are $800 round-trip. But who knew that Dallas to Honolulu, same dates, is $300? Or that you can fly from Houston to Dallas for $100 and connect onward? A savvy travel agent.

Getting a refund when the fare drops after you buy

Several domestic US airlines will give you a full refund, in the form of a voucher good for future travel, if the airfare drops between the time you buy and time you fly -- if and only if you fly on the same itinerary. Find details in this chart.

Factor in the fees

A low fare on one airline could turn out to be not so low once fees are added on. Airlines are making most of their profits these days not from selling you airfares but with all those fees for baggage and other perks. In addition to checked bag fees (chart) there are even fees for using your frequent flyer miles and for other services such as changing a travel date or bringing a pet on board.

Is there a "magic" hour or day to buy?

In a word, no. It's true that the airlines' weekend deals come out Monday to Wednesday, and some airlines announce their sales early in the week, but if you limit yourself to searching just on those days, you'll miss out. A good fare can pop up any moment of the week.

Best days to travel
Although a low airfare can appear at any time, one thing's for certain: it's cheaper to fly on a Tuesday or Wednesday. Saturday is also a low-fare day. If traveling internationally, Monday to Wednesday is often the sweet spot.

Airfare predictions

Speaking of "when to buy," Bing.com/travel purports to offer accurate airfare predictions, indicating whether the site thinks a fare will go up or down, and it's certainly worth a try, but it's not always accurate. To see if an airfare is currently on the high or low side, do a web search for "historic airfares" to see airfare trends on a particular route. Two useful sites: Farereport.com and Kayak.com/trends.

Question? Comment? Follow us @Airfarewatchdog on Twitter! And find us on Facebook.

By George Hobica Airfarewatchdog.com

When Martha Toomey's husband Oscar died, she happened to know the user name and password to his Delta frequent flyer account, and has been helping herself ever since to his 500,000-plus SkyMiles, which is why we've changed her name for the purposes of this article.

You see, what Martha is doing isn't strictly "legal." Posthumously, Oscar has sent his widow on a trip to Europe in business class and on several jaunts to visit her grandchildren in Boston. "I've just been pretending that he was still alive because I was afraid that I would either lose his miles or pay a big transfer fee," the Los Angeles-based retiree confesses. The "legal" way for her to use her late spouse's miles would be to fill in some paper work and request that the miles be transferred to her name as his heir, indeed perhaps paying a transfer fee with some airline programs.  

Most airlines do make it easy to transfer miles between the living, for a fee; but it's an expensive proposition, even when there are occasional transfer bonuses, sometimes as high as 100 percent. Plus, there are mileage transfer limits with these offers. United, for instance, allows any member to transfer between 5,000 and 15,000 miles per recipient per year for $0.015 per mile and a $35 fee. Only 60,000 miles can be transferred per year.  

And despite the fact that many airlines issue blanket statements in their rules that miles are not transferable, period, Airfarewatchdog has found that the airlines do in fact allow miles to be inherited, or to be awarded in a divorce settlement, and you'll get an entirely different answer from what you see on the airlines' web sites if you give a call to their frequent flyer service departments, as this chart shows.  

Take American for instance: their rules plainly state that miles "are not transferable upon death". Well that sounds pretty conclusive, right? Except then we read a few lines later that, "However, American Airlines, in its sole discretion, may credit accrued mileage to persons specifically identified in court approved divorce decrees and wills upon receipt of documentation satisfactory to American Airlines and upon payment of any applicable fees." So does that mean they fork over the miles or not? Turns out that if the AAdvantage account has fewer than 10,000 miles, there's no fee required (only proof of death is needed); if more than 10,000 miles, you'll pay a transfer fee of $50. Continental, in contrast, doesn't charge a fee for transferring miles to an heir.   

But why pay a fee and deal with the airlines at all?

Why not take the Toomey approach by pretending your deceased love one is still alive? Well, for one thing, this is against the rules, and if you're caught your miles will be forfeited. We're not suggesting you do this. We're just saying you could.  

But for those of you collecting miles in the future, if you'd like to avoid having to beg or pay for miles once a family member dies, there are two earning programs you should consider. One is the British Airways Executive Club, which allows you to set up a household account with up to four people living at the same address. Miles earned by one member are combined with those earned by the other three, and can be redeemed by any one of the four. BA lets you spend miles on American and other airlines.

The other option is the American Express Membership Rewards program. Here you can earn miles on about 20 US and foreign airlines. The points never expire as long as you keep them in your Amex account, and you transfer them to the airline frequent flyer program of your choice, where they become miles, as needed. If you and your spouse have a points-earning card for the same account, either Card Member has control of the points and can use them at will as long as the "primary" member authorizes another card member to use them. All it takes is a simple phone call; no fees, no paperwork.

Follow us on Twitter @airfarewatchdog

In the short term, not a lot, unless you’re an American employee, retiree, stock or bond holder, or vendor. American will keep flying, honor all reservations and travel vouchers, and all frequent flyer miles.

In fact, there may be a silver lining, again in the short term. If past filings are any prediction, we may see the airline attempt to lure reluctant consumers by offering bonus frequent flyer miles and perhaps a fare sale. And if people shun American, it might be easier to find seats for frequent flyer award travel.

On the minus side, anyone flying on American in the coming weeks and months will have to deal with even lower employee morale. After all, the whole point of this filing was to lower labor costs and bring them in line with those of airlines that previously filed for Chapter 11 as well as with low cost carriers formed after deregulation.American’s flight attendants, baggage handlers, gate and ticket agents and reservationists will earn less and their pensions are in jeopardy. You may not see too many smiles on your next flight.

But in the longer term, it’s anyone’s guess. True, Continental, Delta, United, US Airways, and Northwest filed for Chapter 11 in the recent past, but those filings ultimately resulted in consolidation, which has led to higher airfares and less competition. Today, the U.S. really only has two large “reasonably healthy” legacy carriers—United and Delta. Southwest Airlines is doing fine, although not exactly flourishing, but US Airways is relatively small and still dealing with its messy acquisition of America West, and now American is ailing. That leaves a handful of smaller niche carriers—JetBlue, Virgin America, Hawaiian, Alaska, Frontier, Spirit, Allegiant, some of which are not consistently profitable. Over the last few years, we’ve lost Aloha, ATA, and Mexicana to Chapter 9, not to mention TWA, Eastern, Pan Am and other carriers, and Midwest and Airtran, among others, to consolidation.

In short, the U.S. airline industry is suffering.

Meanwhile, foreign airlines are hoping to siphon off high-value business travelers and other flyers on international routes. For example, highly profitable and growing Emirates Airlines has its sights aimed on the U.S. market and has ambitious plans for adding U.S. gateways, including Atlanta, Boston, Chicago, Dallas, Detroit, Philadelphia, Seattle and Washington (it already flies from New York, LA, San Francisco and Houston). As other analysts have noted, a profitable business class flyer jetting from Dallas to an international destination can fly on an ailing American Airlines or they might prefer connecting through Dubai on Emirates and enjoy newer planes and better service. That could spell trouble for what’s left of the U.S. airline industry.

Question? Comment? Follow us @Airfarewatchdog on Twitter! And find us on Facebook.

Every Thursday at 6:50 a.m. ET (repeated at 10.50 a.m.), Airfarewatchdog's George Hobica helps the Weather Channel's Al Roker scout out some enticing last minute travel deals for the coming weekend on Wake Up With Al.

Here's our pick of three great destinations/routes. Watch Al's show on Thursday to see what the weather will be when you arrive. And scroll down for links to the airlines' last minute weekend web pages.

Washington to Mexico City $350 round-trip including tax on United

Depart Saturday, return Tuesday

4 suitcases

Source: United.com

Houston to NW Arkansas Airport (Fayetteville) $158 round-trip including tax on Continental

Depart Saturday, return Monday/Tuesday

5 suitcases Source: Continental.com

Newark to Savannah $220 round-trip including tax

Depart Saturday, return Monday

5 suitcases

Source: Continental.com

Turkey in Turkey Thanksgiving Special:

Chicago to Istanbul $644 round-trip including tax

Depart Wednesday, November 24; return Monday, November 28

4 suitcases

Source: Kayak.com

This week's Delta last minute weekend fares

This week's US Air E-Saver weekend fares

This week's Airtran last minute weekend fares

This week's American Airlines last minute weekend fares

This week's United Airlines last minute weekend fares

This week's Continental Airlines last minute weekend fares.

By George Hobica

Airfarewatchdog.com

Everyone knows that smartphones are changing the way we travel – but at what cost?

Sure, one never need be lost in, say, Sao Paulo, ever again, thanks to the magic of Google Maps and a little thing called GPS. But one also may die of a heart attack once the bill for that little getting-out-of-a-jam lands on your doorstep back home. Think it can't be as much as your plane ticket down? Think again.  Remember that Tokyo earthquake? I was there, and navigating my way back to the hotel and sending a few panicky text messages cost me nearly $800 (thankfully, AT&T took pity and reduced the bill to $25 by retroactively adding a data plan--see below). 

Be a smarter smartphone user. We'll show you how.

Buy a cheap disposable. This is what I do when I roam overseas. In many cities, it's easy and cheap to buy a throw-away mobile phone. True, this won't be a "smartphone," (the kind that allows you to use Google maps, mobile apps, and browse the Internet) but it will allow you to "pay as you go" at reasonable per-minute talk rates. Ask your local contacts (such as hotel or airport staff) where to buy or just do a Google search. In London, for example, drop into any Orange shop (or other service provider) and you can pick up a cheap throwaway for a few (as in five or so) quid. Maybe you won't be able to run your office off the thing, but at least you've got cheap talk connectivity for the equivalent of a few dollars. (Sadly, it's very difficult if not impossible to buy an iPhone or other smartphone service plan overseas unless you're a local resident with established credit or an ID—such as a local drivers license or a utility bill. However, if you're a frequent visitor and you have family or close friends in, say, London, you could have your local contact set up smartphone service and simply reimburse the cost).

If you bring your own phone. Two things you should sort out immediately. One, will your phone work overseas -- this will enable you to make and receive calls, as well as send text messages. Two, will you be able to access a data network, and if so, how much will it cost? To answer this, you'll need to start by figuring out what kind of phone you've got.

GSM or CDMA? When Verizon got the iPhone, did you rush out and get one? If you're heading to Europe, maybe you should have called AT&T instead. AT&T's version of the iPhone is a so-called world phone, meaning it operates across both the CDMA and GSM networks. Verizon's iPhone 4 is a CDMA phone, meaning its powers are useless in places like Europe – in fact, outside of North America, you're basically out of luck. Stupid? You bet. That’s why, if you haven't already taken the plunge, you need to get the 4S. That's a worldphone.

Swing both ways. Ideally, if you're more than an occasional traveler, get a world phone, which works everywhere, across all networks and frequencies (some GSM phones do not do this). Ask your provider which phones meet the requirements; AT&T's iPhone is one. The Motorola Droid 2 Global phone from Verizon is another. 

Ready, set, roam. Each provider offers an international roaming program for calling, texting and data. For example, you can contact T-Mobile and have them add international roaming. You'll pay as you go – calls start at 40 cents a minute and climb from there, while data goes for $15 per megabyte (MB) ($10 in Canada.) More info on t-mobile roaming charges here.

 AT&T Wireless offers "affordable" international data packages starting at $25 per month going up to $200 per month. Of course, affordable is in the eye of the beholder. The entry plan gives you 50 MB of data in over 100 countries, and $10 per additional 10 MB; the top tier plan gives you 800 MB of data per month. AT&T has a handy international roaming data calculator to give you an idea of how much overseas roaming might cost you. (You'll quickly learn that most people will quickly burn through even the most "generous" 800 MB plan).

If you go this route, make sure you change your phone's data settings – anything set to sync or update automatically should not be doing so while you're out of the country, unless you're hooked up to wifi – that all costs money. 

PS? Roaming is for suckers. While it may feel good to be connected wherever you go, roaming is really not the best way to do this. You have two other – and better -- choices. One, unlock your phone and slip in a new SIM card from a local provider in your destination. In many places, you can buy a cheap, pre-paid SIM (think of it as a slightly more technical phone card), slide it in and suddenly you're calling and surfing like a local. All you need to do is make sure your phone is unlocked – AT&T (some iPhone users) and T-Mobile customers in good standing, for example, should have no problem; just ask. (With legally unlocked iPhones hitting the market in the United States right now, this will all change.) For peace of mind (and no running around looking for SIM cards when you land in a strange country), try National Geographic's Cellular Abroad service, which will fix you up for that next trip to Timbuktu.  

Boom. It's a computer. While it's great to have roaming capability (or, better yet, a local SIM card) in case of emergencies, the fact is, these smartphones are actually tiny little laptops with phone capability. Before you leave home, print out a map of your destination and mark down all the free wireless hotspots you can find by researching online and just regulate your use of your phone to those places. Better yet, rent a pocket hotspot or a smartphone from a company like Tep Wireless. (Tep claims that its per-MB data charges are 90 percent less than typical roaming charges). Wherever you go, you're connected. Also: Download Skype or Vonage to your phone and you're now entirely capable anytime you've got Internet access. 

Here we list, airline by airline, fees for ticket changes (non refundable fares); booking fares in person or by phone, kids flying solo, bringing a pet into the cabin, and booking fares other than online. As you can see, Southwest has the lowest and fewest fees, followed by other low cost carriers such as Airtran and Spirit. Note that most of these fees, unless otherwise noted, are for domestic flights; fees for international services may be higher. Last revision: Nov 2 2011.

See also: New airline frequent flyer program fees 

By George Hobica

Airfarewatchdog.com

It used to be all so simple, back when airfares changed so infrequently that airlines actually printed them on their schedules. You'd call your favorite travel agent to find the best deal, pack your bags, and jet off. And there were only two kinds of fares: coach and first class.

Now, with airfares changing literally by the second and an alphabet soup of different offers, finding the "best" deal is a challenge. But don't give up hope. This step-by-step guide will get you ready for takeoff.

Sign up for free airfare alerts 

Why do all the work hunting down a low airfare yourself when you can have someone else do it for free? Many airfare search and listing sites, such as TripAdvisor.com/flights, Travelocity.com, Farecompare.com, Hotwire.com, and Bing.com/travel (and, of course, Airfarewatchdog.com) offer e-mailed airfare alerts when prices go down. This chart compares many of the leading airfare alert sites. (By the way, only Airfarewatchdog lists fares on Southwest Airlines).

Get e-mail from your airlines 

Next: Sign up for e-mails and frequent flier programs. Airlines are trying to woo customers to book directly with them by offering special deals when you subscribe.  Here's where to sign up for emails from foreign-based airlines and here from U.S.-based carriers.

Next step: are you a flexible travel date flier? 

Doesn't really matter when you go as long as it's cheap? Some websites offer flexible date search up to 330 days ahead; others (mostly those powered by a company called ITASoftware) only do searches in 30-day increments.  Learn more about flexible date searches on major sites.

These sites can be helpful if your dates are set, but you also might want to try "meta search" sites such as Kayak.com, Tripadvisor.com/Flights, and Momondo.com.  Warning: None of them include Southwest's fares, however, or fares on the smaller but growing Allegiant Airlines.

"Meta search" vs. online travel agency (OTA) 

So what's the difference? For one thing, online travel agencies such as Expedia have toll-free numbers with agents standing by to help you book or re-book a flight; meta-search sites don't. But there are many other differences.

Airline websites sometimes have the best fares 

Increasingly, airlines aren't sharing their very best fares with third-party sites such as Kayak. Case in point: recent fares to London from the West Coast for $420 round-trip including tax that were only available on Spanish airline Iberia's website (similar fares were twice that elsewhere). So once you've found a fare, definitely check airline sites directly.

Watch out for promo codes 

From time to time, you'll receive promo codes in your e-mail because you signed up for e-mail from your favorite airlines and online travel agencies. These codes can only be redeemed if you book directly on the airlines' websites, another way they try to cut out the middleman.

When to use your miles 

Rather than cashing in 25,000 or even 50,000 miles for a domestic economy class ticket that might have cost you $250 or $300, why not splurge for a trip to Europe (50,000 miles on some airlines) that might cost many times more; or upgrade your $400 economy class seat to a $2,800 business class fare for 30,000 miles on domestic routes? A general rule: if the economy class fare is $400 or more, spending 25,000 miles is a good deal. Less than that, you might be better offering paying cash and saving your miles.

Getting the best last-minute airfares 

You'll often get the best fares if you book at least 7 to 21 days ahead of departure. Otherwise, your best bet is Priceline.com's "Name your own price" feature or Hotwire.com. Also take a look at Lastminute.com which packages last minute airfares with hotel and rental car deals—sometimes for less than what you'd pay for airfare alone.

When to use a real live travel agent 

As good as do-it-yourself online sources can be, your friendly neighborhood travel agent may have some tricks up her sleeve to save you money. Let's say, for example, that you get an airfare alert that fares from Houston to Honolulu are $800 round-trip. But who knew that the fare from Dallas to Honolulu, same dates, is going for just $300. Or that you can fly from Houston to Dallas for $100 and connect onward? A savvy travel agent.

Getting a refund when the fare drops after you buy 

Several domestic U.S. airlines will give you a full refund, in the form of a voucher good for future travel, if the airfare drops between the time you buy and time you fly—if and only if you fly on the same itinerary. Most foreign-based airlines won't however. Details here.

Watch out for fees 

A low fare on one airline could turn out to be not so low once fees are added on. Airlines are making most of their profits these days not from selling you airfares but with all those fees for baggage and other perks.  In addition to checked bag fees (see chart) there are even fees now for using your frequent flyer miles and other services such as changing a travel date or bringing a pet onboard.

Best days to travel 

Although a low airfare can pop up at any moment, one thing's for certain: it's cheaper to fly on a Tuesday or Wednesday. Saturday is also a low-fare day. If traveling internationally, Monday to Wednesday is often the sweet spot.

Is there a "magic" hour or day to buy? 

It's true that the airlines' weekend deals come out Monday to Wednesday, and some airlines announce their sales early in the week, but if you limit yourself to searching just on those days, you'll miss out. A good fare can pop up any moment of the week.  

Airfare predictions 

Speaking of "when to buy," Bing.com/travel purports to offer accurate airfare predictions, indicating whether the site thinks a fare will go up or down, and it's certainly worth a try, but it's not always accurate. To see if an airfare is currently on the high or low side, do a web search for "historic airfares" to see airfare trends on a particular route. Two useful sites: Farereport.com and Kayak.com/trends.

Also worth reading:

"Hidden City" fares can save money, but sometimes at great cost

Holiday airfare savings tips

Time to rethink what a "cheap" airfare is?

What's the difference between an "online travel agency" (OTA) such as Expedia, Orbitz and Travelocity vs.  so-called "meta search" travel site such as TripAdvisor Flights? For one thing, online travel agencies have toll-free numbers with agents standing by to help you book or re-book a flight; meta search sites such as Kayak don't, because they don't sell airfares; they send you directly to airlines or to online travel agencies to book. Both an online travel agency and a meta search site will let you know if the best deal is on a combination of airlines (say, going out on US Airways and coming back on United).

But neither type of site will show you fares on all airlines (Southwest and Allegiant are excluded) and neither will always have fares that the airlines are keeping for their own websites (airlines sometimes hold back fares and inventory for their own sites in order to entice users to book direct).

But, unlike airline sites which try to keep you on the airline's own network, OTAs and meta search websites do show you the widest range of schedules and fares. Occasionally, an online travel agency such as Expedia or Travelocity will have fares that meta search sites don't. For example, over the summer American Airlines had business class fares to Europe for peak summer travel at prices lower than economy class for the same dates; Travelocity had these deals, Kayak didn't. In general, however, meta search sites do a better job of finding "airline-site-only" fares than do online travel agencies. On the other hand, online agencies offer air plus hotel packages that can sometimes save you serious cash, whereas meta search sites don't.

Bottom line: you need to consult meta search sites, online travel agencies, and airline sites if you really want to find the best deal.

Follow Airfarewatchdog on Twitter @airfarewatchdog to track unadvertised airfare sales that sometimes last only a few hours.