Q. I'm just wondering: what would happen if I were to take a connecting flight from New York to Austin, TX, with the connection being in Houston, and I stayed in Houston and did not continue on to Austin. This would be a one-way ticket. Would there be any fees or complications associated with such a thing?

A. I'm assuming that you wish to do this because the fare from New York to Austin connecting in Houston is less expensive than the fare from New York to Houston. What you're proposing is called in "hidden city" fare in airline parlance. Many airlines forbid this practice in their contracts of carriage, but some do not. And were you to do this on a round-trip ticket (New York-Houston-Austin-Houston-New York) then the airline would cancel the Austin-Houston-New York portion of your trip if you didn't shown up for the Houston-Austin leg. Even those airlines that forbid the practice won't go after your bank account, however if you do this often they might kick you out of their frequent flyer program. To play it safe, if your airline has regulations against the practice then don't use your frequent flyer number.

Q. My wife and I are contemplating a trip to China (Beijing, Shanghai, and Hong Kong) and are wondering when is the best time to travel there and to buy airfares. This would be our first trip to Asia. Is there are website that has the cheapest fares? Should we book a package deal or travel independently? What's the best airline to use? Also, my wife has respiratory problems and has to fly with a portable oxygen concentrator so we're wondering what the airline policies are about bringing oxygen on board the plane.

A. Let me address your last question first. If your wife has respiratory problems, I would seriously reconsider a trip to China's major cities. Due to industrial expansion and other factors, the air quality is horrendous. Even people with healthy lungs find it intolerable some days. Friends of mine who moved to Beijing for work with their two small children quickly asked for a relocation to Singapore when they discovered how bad the air quality was in China. For a first visit to Asia, I'd follow their lead and visit Singapore instead. (Singapore is fast becoming the tourist hub of Asia with excellent hotels, infrastructure, attractions (they even have casinos and a Universal Studios theme park now), excellent shopping and cuisine.) But if you insist on visiting China, I would fly on an airline with clearly stated rules on traveling with a portable oxygen concentrator, such as United or Singapore Airlines. This article spells out United's policies, and here are Singapore's rules. And wherever you decide to go, definitely look into package deals since they often save money over buying hotel, airfare and tours a la carte. Sign up for Singapore Airline's frequent flyer program (Kris Flyer) to get first dibs on special promotions, which are often sent to members before they general public.

Q. For obvious reasons, I am not going to tell you the name of the airline, and probably shouldn't even be asking this question in a public form, but here goes: last December, I cashed in some miles to obtain a frequent flyer award ticket. Lo and behold, on my January frequent flyer statement I was awarded full frequent flyer miles on the free flight (about 6000 miles). As anyone can figure out, this was some kind of computer glitch. My question: if I "spend" those miles on a future trip, will the airline discover their error and come back to me and charge me for the flight I used them on? I realize you can't predict airline business practices, but just wondering if you've heard of a similar situation.

A. As you probably know, this is a highly unusual situation. With airlines merging and changing their frequent flyer programs, websites, and computer systems, mistakes are bound to occur. I'd say the worst that could happen is the airline will deduct the miles from your account at some future date if they discover the error, but more likely they'll just let it go. It's probable that you weren't the only one who got a little holiday "gift" in this software snafu. Of course, you could bring this to the airline's attention if you want to be an honest Abe.

Q. Is Heathrow the only international airport that prohibits you from carrying more than one bag onto a plane? Even if your one piece of carry-on luggage is accompanied by nothing more than a tiny purse (let alone a normal-sized briefcase) they make you check your bag. It seems outrageous.  

A. London's Heathrow Airport does not have a rule limiting carry-on bags to one item per person, although it did at one time as a result of heightened security measures. However, your airline can impose its own limits (both on the number of items and on their size and weight) and perhaps that is what you experienced. Many airlines now weigh carry-on bags at check in (or even at the gate) and have maximum weight restrictions as little as 10 or 12 kilograms (or 25 pounds or less). I recently flew on an Airbus A380 and noticed a warning on the overhead bin that the maximum weight for the bin was 50 kg, so perhaps that's the reason for weight limits (maybe the overhead bin would break or fail to operate properly if there were too many heavy bags).

Q. I read that I could get 50,000 frequent flyer miles for opening a new Fidelity Investments account of $100,000 but I cannot find that deal mentioned anywhere online. Do other banks have similar deals?

A. United, American and Delta Airlines offer up to 50,000 frequent flyer miles when you open and fund a nonretirement account at Fidelity Investments of $100,000 or more; or 25,000 miles for an account worth $50,000 or more; or 15,000 miles for an account worth $25,000 or more. US Airways offers up to 25,000 miles for investing $50,000 or more in a TD Ameritrade brokerage account. To find links to these offers, simply web-search "[airline] + Fidelity Investments" or "US Airways Dividend Miles + TD Ameritrade."

Q. If traveling with a small pet under the seat in a pet container are there any charges for the pet and, if not, is the pet and its container considered your carry on or are you allowed one carry on along with the pet?

A. Airlines do indeed charge a fee for pets carried in the cabin, and the fee varies between airlines. United Airlines, for example, charges $125 each way. Southwest charges $75 each way. You can easily find the fee for your airline by web-searching "[airline] + pet fee." Airlines limit the number of pets per cabin, so you should reserve a spot for your little buddy by phone at the same time you book your own flight. Make sure that your pet's container is small enough to fit in the seat in front of you (and that you don't book a bulk head seat, which won't have under seat storage). And unfortunately, your pet's container does count as your one carry on piece. The above information applies to domestic U.S. flights; fees and regulations may vary for international travel so check with your airline before booking your trip, and these fees and policies are subject change without notice.