US Airways said in a regulatory filing that it has cut its capacity by 2% for the year's second half.
More U.S. airlines have been moving to cut domestic capacity recently, as they battle weakening results. By holding the supply of airplane seats in check, the industry allows itself greater pricing power.
US Airways cited "industry conditions" for its decision to trim capacity in the filing Thursday.
The airline said it expects to have about 19.5 billion available seat miles in the third quarter and 18.9 billion in the fourth quarter, compared with 18.6 billion in the first quarter and 19.5 billion in the second quarter.
An available seat mile is an industry unit measuring one airplane seat flown one mile.
US Airways also said Thursday that it filled a higher percentage of seats in June than in any month in the company's history -- reporting a "load factor" of 85.3% in June, up from 83.7% for the same month in 2006.
For the month of June, the airline reported that its capacity was down 1.4% and revenue passenger miles were up 0.4% from June 2006.
"Looking forward, we see an encouraging revenue environment moving into the third quarter due, in part, to stronger year-over-year bookings and improving yield trends," US Airways President Scott Kirby said.
In June, about 62% of America West and US Airways flights arrived within 14 minutes of the scheduled arrival time, and 2.8% of its flights were canceled.