I'm not familiar with US Airways upgrade policies, so I can't be specific. However, I can give you some general guidelines on how most airlines work.

First off, you didn't give us the most important piece of information to answering your question, and that is whether you're asking about a domestic or an international flight upgrade. There's a whole different set of rules for each.

The other factor involved is whether you are an elite member of their mileage program. Since you know little about the upgrade system, I'll assume you're not. An elite member is generally one who flys at least 25,000 miles yearly with that particular airline.

So without having much information to go on, what I can tell you is that you can buy a coach class tkt and then use miles for an upgrade. A domestic upgrade is usually about 20,000 miles rountrip and an international one is usually about 50,000. Again, this number varies from carrier to carrier, but I'm giving you what most charge. On top of that, if you're not an elite member, you usually can only upgrade from a certain fare basis. Within coach, every booking has a class that has a letter assigned to it......H, K, etc. What this means, is that if you didn't pay enough for your seat, you can't use miles for an upgrade.

For example, I'm Gold Elite with American Airlines (AA) and because of that I can use miles to upgrade to Biz Class for my international no matter what fare basis I've paid. I can often get a $400.00 tkt and then upgrade. For someone who's not elite, they'd have to pay approx $800. for their seat to be able to upgrade. On top of that, there's the concept of Yield Management which tells them exactly how many seats they'll allow for upgrading with FF miles vs. actual dollar revenue. IOW, there might be plenty of seats available, but not available for upgrading. As they get closer to the flight, these numbers change and seats may open up as late as just hours before the flight.

Domestic upgrades are often done with upgrade coupons. These are usually purchased in blocks of 500 or 1000 mile coupons. So for example, if you wanted to upgrade for a flight from NY to LA which is 2475 miles, you'd have to use 2500 worth of coupons. I don't recall the price of the coupons, however, elite members will pay less for them as well as get priority on using them.

Lastly, you can only upgrade one class in a 3 class plane. In othe words, you can't buy coach and buy an upgrade to First, only to Biz.

On a final note, if you're not going to upgrade, ask about the pitch (legroom) and go for the airline which gives you the most. American's More Legroom Thru Coach has made a wonderful difference in comfort. Though they are adding seats and doing away with that comfort on some of their routes, it's still available in most. It makes a huge difference and I've switches alliances to American because of that added legroom.

I realize you asked the time and I've told you how to make a watch, but I didn't know how to explain it any simpler. I hope I've answered some of your questions.

Candice NYC