Per-seat passenger revenue for September was flat compared to September 2011, the airline said.
For September, traffic rose 2 percent. Capacity rose 1.1 percent. That pushed occupancy up 0.7 percentage points, to 84 percent.
Shares of US Airways Group Inc., based in Tempe, Ariz., jumped 99 cents, or 9.1 percent, to $11.87 in midday trading. They've traded between $3.96 and $14.51 over the past year, boosted by the airline's improving financial prospects and its ongoing efforts to merge with American Airlines.