Big changes may be coming to the process of buying aifares. That's because ATPCO, the folks who act as the airfare intermediary between the airlines and you, the consumer, via airfare distribution systems such as Travelocity, Expedia, and your local travel agent, will soon be implementing real time, instantaneous airfare updates, according to a person who is familiar with the matter.

Currently, ATPCO (the Airline Tariff Publishing Company) allows airlines to "file" new fares three times a day (10 AM, 12:30 PM, and 8 PM) weekdays, and once a day (5 PM) weekends. But the company, I was told, has been working on a major software update that will allow airlines to file new fares with ATPCO whenever they want, 24/7, even on weekends. (Airfare factoid: the last fare update at 10 PM 8 PM on Friday has been a popular one for the airlines to sneak in a fare sale, since their competitors can't match it until the 5 PM Saturday update, but looks like that strategem will be one for the history books).

This could have huge implications for both the airlines and you, the consumer.

What it means for you is that fares can fluctuate much more frequently than before, which may make shopping for airfares even more of a challenge.

What is means for airlines is that in order to respond to their competition's airfare increases and decreases, they could conceivably have their pricing analysts work in a 24 hour environment. On the plus side for airlines and the online travel agencies such as Travelocity, they'll be able to eliminate fare mistakes almost instantaneously instead of waiting for the next fare update, which could be hours away. On the minus side, airlines might have to add staff to their pricing and fare analysis departments, and really keep on their toes.

Interestingly, the major airlines own ATPCO, but their primary customers are actually the global distribution systems (GDSs) such as Sabre (as well as anyone else who wishes to buy their voluminous--and very costly--airfare data, for example, ITA Software). It appears that the customers are the primary impetus behind this change, rather than the owners themselves.

Of course, there's many a slip between development and launch when it comes to new software, but if this project is successfully implemented and potential conflicts of interest are resolved, airlines will be able to change their fares more often and more quickly than ever before, and consumers will need to keep on their toes like never before.

The new summer sale from Midwest is good for Tuesday-Wednesday travel from April 20 all the way through September 30. All fares require a 21-day advance purchase and, in some cases, a one-night minimum stay. Sale ends April 8 and fares include:

Appleton to Nashville $168 round-trip

Des Moines to Indianapolis $168 round-trip

Flint to Las Vegas $218 round-trip

Green Bay to Denver $218 round-trip

Kansas City to Dayton $168 round-trip

Milwaukee to Minneapolis $158 round-trip

Madison to Cleveland $168 round-trip

Omaha to Dayton $168 round-trip

Here's the latest sale from Frontier, good for Tuesday-Wednesday travel through August 26. All fares require a 10-day advance purchase and must be booked by April 1. Interested?

Fares include:

Albuquerque to Dallas-Ft Worth $178 round-trip

Billings to Salt Lake City $218 round-trip

Colorado Springs to Spokane $178 round-trip

Dayton to Spokane $238 round-trip

Denver to Portland $128 round-trip

Kansas City to Salt Lake City $178 round-trip

Salt Lake City to St Louis $178 round-trip

Blackout dates are April 13, May 21 - 22, May 25, July 2 - 3, and July 5 - 6.

US Air is duking it out with Delta and Continental with peak summer fares to the Emerald Isle in the mid $500's RT including tax.

Check out the fares we've found to Dublin and to Shannon!

JetBlue has launched yet another sale with fares ranging from $39 to $119 each way. And now a message from the guy who writes all that fine print after the asterisk:

Travel must be booked by April 8, 2009, 11:59 PM MT. For travel between Orlando and Puerto Rico: travel must take place between April 15, 2009 and May 13, 2009. For travel between Boston and Bermuda: travel must take place between May 1, 2009 and June 17, 2009. For travel between New York and Montego Bay: travel must take place between May 21, 2009 and June 17, 2009. For all other city pairs: travel must take place between April 29, 2009 and June 17, 2009. Travel must be completed by June 17, 2009. For travel to/from Florida: travel must take place on Tuesday, Wednesday, and/or Saturday. For travel between New York and Aruba: travel must take place on Monday, Tuesday, Wednesday, Thursday, and/or Friday. For travel to/from Cancun, Nassau, St. Maarten, and/or Montego Bay: travel must take place on Monday, Tuesday, Wednesday, Thursday, Friday, and/or Sunday. For all other city pairs: travel must take place on Monday, Tuesday, Wednesday, Thursday, and/or Saturday. All fares are subject to change without notice.

The whole point of a price-drop refund is to save money, right? You buy a ticket, the price goes down, you catch it and request a refund for the difference. It should be that easy, but annoyingly enough, it's not. The airlines who offer these refunds usually tack on some sort of fee that tends to eat up any cash you might have saved.

And these days, with the airlines and the online travel agencies revisiting their price-drip refund policies in an attempt to woo back consumers (just last week, both Travelocity and Priceline added price-drop guarantees), it seems a little bit like a step backwards that United would up their domestic price-drop refund from $0 to $150 per ticket for domestic and Canadian travel. International refunds vary, which is fine print-speak for "way more than $150," we're guessing.

Atlantans looking to head farther south this spring should check out Delta's latest sale to Central American and Mexico. All fares must be booked by March 30 and include:

Atlanta to Belize $574 round-trip, including all taxes

Atlanta to Mexico City $472 round-trip, including all taxes

Atlanta to Monterrey $508 round-trip, including all taxes

Atlanta to Cabo San Lucas $577 round-trip, including all taxes

Atlanta to Tegucigalpa $425 round-trip, including all taxes

This sale is good for travel through May 31, but mind the blackout dates: April 2-14, and May 21-26.

Don't get us wrong. We love all those other sites and use them every day. The only thing is, airlines these days sell many of their best fares on their own Web sites, with special site-only sales, promo code fares, and other deals.

Airlines don't pay folks like us (or folks like Kayak) to refer you, our valued readers and users, to these special fares. So most airfare sites tend not to list these fares in their searches. Gotta pay for all those programmers and venture capitalists, after all. But we do tell you about what we call "airline-site-only" fares, including deals on Southwest, even though we don't get paid for doing so, because Airfarewatchdog.com was founded by a travel journalist (me) specializing in consumer travel issues (I was an English major, not an MBA student, although many of my best friends do have MBAs). So if you're new to our site, please take a look around and sign up for our free alerts.

One thing: those other sites do cover more routes than we do, and their fare alert systems offer some bells and whistles that we don't, so do give them a look, too!

Turning 50 this year? Congratulations! China Airlines is offering free flights to those born in 1959. Just fly with a fully paid passenger, sharing the same reservation, and you're all set. This offer is good for outbound travel between February 20 and April 30, for flights departing from San Fran, Los Angeles, New York, Honolulu, and Vancouver - traveling to Taiwan, Hong Kong, Bangkok, Manila, Delhi and Mainland China. All purchases must be made by March 31.

Here's something we sure didn't see last summer: $500-range round-trip peak summer fares to London? Yep, it's crazy but true. We're finding all sorts of great fares on US Airways to London Gatwick. In some cases, fares are half of what they'd be for London Heathrow -which, yes, do tend to be nonstop but -meh- for these prices, we'll manage.

So far we've found:

Cincinnati to London $672 round-trip, including all taxes

Cleveland to London $599 round-trip, including all taxes

Denver to London $620 round-trip, including all taxes

Los Angeles to London $559 round-trip, including all taxes

Portland to London $549 round-trip, including all taxes

San Diego to London $549 round-trip, including all taxes

San Francisco to London $559 round-trip, including all taxes

Seattle to London $549 round-trip, including all taxes

Yuma to London $635 round-trip, including all taxes

Also strange: the fares we found from Yuma were much cheaper than what we found out of Chicago. Makes no sense to us but that's how it is.

For a complete list of fares, be sure to visit our London Gatwick page.