DALLAS (AP) — Summer has come and gone without giving much lift to the nation's airlines.

The carriers offered fewer flights than a year ago, and they slashed prices to fill even that reduced supply of seats, according to August traffic reports released over the past week.

Discount airlines fared relatively better in the recession, as they lured vacationers with cheap fares.

Business travel remained extremely weak. Airlines don't break out figures for business travel — they aren't always sure whether passengers are flying for work or pleasure — but numbers from Continental gave a glimpse of the corporate-travel slump.

Continental regularly discloses a statistic called revenue per available seat mile, a closely watched indicator of financial performance in the airline world. The Houston-based airline estimated that the key measurement fell 17 percent from August 2008. That's four times faster than the drop-off in traffic, and it indicated that many of the missing passengers are business travelers who used to pay top dollar for their seats in the front of the plane.

By this revenue-per-capacity measurement, August wasn't quite as weak as July.

Kevin Crissey, an analyst for UBS, predicted that September will be worse — perhaps down more than 20 percent compared to September 2008.

But Helane Becker, an analyst for Jesup & Lamont Securities, said there was "a little bit of a rebound" in August figures, with smaller declines than in July. She said last-minute bookings and business traffic appear to be improving for September.

Jamie Baker, an analyst for JPMorgan, said Thursday that demand is "weak, but not as bad as feared."

Baker upgraded stock in the parent companies of United Airlines and US Airways, citing less fear that they could be forced to seek bankruptcy protection. He said in a note to clients that he now expects all the major airlines to survive the slow winter period without filing for Chapter 11 help.

The JPMorgan analyst boosted United parent UAL Corp. to "overweight" from "underweight," and raised US Airways Group Inc. to "neutral" from "underweight." To offset those upgrades, Baker lowered JetBlue Airways Corp. and AirTran Holdings Inc. to "neutral" from "overweight."

The nation's four largest airlines all handled less traffic than they did in August 2008. Traffic is measured in miles flown by paying passengers.

August traffic fell 2.2 percent at Delta Air Lines Inc., the world's largest airline company; 8 percent at A

American Airlines parent AMR Corp.; 3.3 percent at UAL; and 3.9 percent at Continental.

Two leading discount airlines did better. Traffic rose 1 percent at Southwest Airlines Co. and held steady at JetBlue. But August traffic fell 6.1 percent at AirTran.

The carriers have been reducing flights to cut capacity and match the weaker demand. Delta, including its Northwest Airlines unit, offered 3.2 percent less capacity last month than it did in August 2008. American slashed capacity by 9.4 percent, UAL trimmed 3.3 percent, and Continental cut 6 percent.