The idea of spending extra miles to get the seat you want isn’t universal, you can’t do it with British Airways or Virgin Atlantic miles for instance. Most European and Asian carriers don’t offer this (although some like Singapore Airlines do).
But it’s near-universal for US airlines, though they do it in different ways. United only lets elites and co-brand credit card holders spend extra miles for last seat availability, for instance. General members without a United credit card only get access to most seats at a much higher mileage price. But they have only two mileage levels. Alaska, American, US Airways, and Delta all have more levels.
The US Airways frequent flyer program will combine into American AAdvantage in a few months. (You should link your US Airways and American frequent flyer accounts.) In the meantime they’re bringing the programs closer together. And treating miles from either program the same in redeeming for extra award space on the other airline was one step towards that.
It worked well on the American website, using American miles for US Airways flights.
Apparently it was glitchy on the US Airways website, using US Airways miles for American flights. So it was quickly taken down.
The ability to use US Airways miles for last seat availability on American flights at a higher mileage cost is back. The catch is you have to call US Airways in order to book those flights. US Airways, however, won’t charge a telephone booking fee for awards that cannot be reserved on its website.
Medium / High Awards:
With no blackout dates, you can use your miles for any seat on any US Airways and/or American Airlines flights. Medium / High award mileage levels vary by date. For Medium / High awards that include travel on American Airlines, please call US Airways Reservations at 800-428-4322.
If this was more than a simple and easy fix it wouldn’t make sense to invest in the Dividend Miles online architecture with only a few months left for the program itself before it’s merged into AAdvantage.