Several large airlines raised fares on some U.S. routes Wednesday by up to $10 per round trip.
US Airways, United, Continental and Delta confirmed that they raised prices.
Jamie Baker, an analyst for J.P. Morgan Chase, said the increases of $6 to $10 were applied to last-minute tickets favored by corporate travelers.
He said the move, led by US Airways, appeared to back up the company's comments that demand for business travel has held up.
Baker said the airlines did not increase prices on tickets requiring an advance purchase. Those are usually bought by leisure travelers.
US Airways reported this week that traffic increased last month compared with August 2010, and a closely watched revenue figure -- passenger revenue per mile --grew 9%. Southwest said the same figure rose 6%, suggesting that travel demand remains stable and airlines can charge higher prices than a year ago.
Airlines sometimes increase prices only to roll them back if competitors don't match. Baker said the fate of the US Airways-led increase would depend on discounters, notably Southwest.