02/23/2012 07:07 am ET Updated Apr 24, 2012

Ask Airfarewatchdog: A Surprise 'Gift' Of Frequent Flyer Miles, Clearing The Air About A Trip To China answers your questions about air travel. We answer as many as we can in this column or by email to

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 6,000 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: 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 -- plus 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; here are Singapore's. 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.