This is one of those tips that if you didn’t know it already, you will never forget it and you’ll wonder why you didn’t realize it already.
US Airways upgrades all of its elites 48 hours out from flights. (Chairmen are 7 days out, Silvers are two days out). If you are booking a last minute trip–that is, within two days of leaving–you can easily pick and choose between flights you are very likely to get an upgrade on and flights you are very unlikely to get an upgrade on.
I just booked a last minute trip for work. Unfortunately, my time wasn’t so flexible that I could pick the flights where I would get upgraded, but it was very easy for me to see that I was not going to get upgraded. It keeps me grounded in my expectations at least!
When you are booking less than 48 hours out as an elite, there’s an extremely, extremely high chance you’ll grab any open first class seat there. US Airways algorithm runs multiple times a day, so even other elites booking last minute trips would need to book them around the same time as you to grab that seat first.
So if this were my trip to Boston:
The first flight, my chances of getting an upgrade are approaching 0% because there are no open seats in First Class for sale (though still possible because this is a shuttle route and people shift flights more often on a shuttle route).
But for my flight back, my chances of an upgrade are approaching 100%, even if I were a silver instead of a chairman. The chances of any open seat going to you is so enormously high that you only need to see seats for sale in first to be fairly confident you will get them.
Occasionally, US Airways won’t open upgrades until a few days out from a flight. This confuses the Silvers because first class looks empty, but once the algorithm runs on their upgrade day, there are no seats for them in first. I’ve never seen this happen where the upgrades did not open until within 48 hours of a flight. It is still technically possible, so YMMV, but I think you can be fairly confident in your chances of upgrade based on booking availability alone.
Unfortunately for me, on the flights I actually booked, all the first class seats were sold out!