It’s a very good idea to look at the fares on American Airlines’ website as well. As Ely Portillo of the Charlotte Observer explains:
If you’re flying from Charlotte to Vancouver at the end of August, you’ll pay $1,500 on US Airways and $877 on its merger partner, American Airlines.
The twist? It’s the same flight, on the same plane. The only difference is which carrier’s website you use to book your ticket.
That’s because even though the airlines merged in December and now sell tickets on each other’s flights, they haven’t yet merged their reservation systems. Because of lags in the computer systems used to display ticket prices, the same flight can appear for hundreds of dollars more or less, depending on whether you search USAirways.com or AA.com.