FORT WORTH, Texas — If your most recent flight felt crowded, it was.

Most domestic airlines reported that the load factor — the percentage of seats filled — topped 80 percent for the third quarter as carriers cut flights out of their schedules. So though fewer passengers are flying these days, planes are fuller because fewer seats are available, industry analysts say.

And that trend of high load factors is expected to continue through the holidays.

"Business travelers, who pay three to four times more per ticket, used to subsidize some empty seats, and because airlines don't have that business traveler anymore, they will stick as many low-yielding passengers — all the way to the gills — into a plane," said Rick Seaney, chief executive of FareCompare.com, a Web site that tracks airfares.

Planes are so full that it might be time to rethink that time-honored strategy of accepting money or vouchers for volunteering to be bumped. You just might not get back on anytime soon.

The July-September quarter is traditionally the strongest for airlines as leisure travelers fill up planes during the summer and business travelers start flying again in the fall.

But with the recession, domestic carriers had to drop airfares dramatically to entice vacationers to fly in late summer. They ended up cutting flight capacity in September because business travel demand was low.

As a result, analysts say load factors remained strong, in the low- to mid-80 percent range, in the third quarter. That was true even at Dallas-based Southwest Airlines, which typically has load factors in the 60s and low 70s.

For the third quarter, Southwest reported that its load factor increased eight percentage points, to 79.6 percent, compared with the third quarter of 2008.

"Our load factors have been consistently running at record levels and in some cases beating some long-standing previous records," Chief Executive Gary Kelly said during a recent conference call.

Three of the largest domestic carriers — Continental Airlines, Delta Air Lines/Northwest Airlines and United Airlines — all reported a third-quarter load factor of 85.8 percent.

At Fort Worth-based AMR Corp., American Airlines said its load factor rose 1.7 percentage points, to 83.9 percent, while its regional carrier, American Eagle, saw its load factor rise 3.7 points, to 73.1 percent.

Though passengers are taking advantage of low fares, the lack of business travelers is making it difficult for American to predict how full its planes will be this winter.

"Uncertainty persists about how travel demand will trend," American Chief Financial Officer Tom Horton said during an earnings conference call. He said that American's domestic load factor for the remainder of the year was down about 1 percentage point and that international was flat.

The days of the middle seat being empty on a plane are long gone, analysts said.

As a result of skyrocketing fuel prices in the summer, airlines started pulling planes out of service because flying them half-full was too expensive. When corporations cut travel budgets during the recession, airlines decreased their flights schedules even more.

"Since the airlines have downsized so much over the last two years, the load factors are going to remain pretty high," said Tom Parsons, chief executive of BestFares.com, an Arlington, Texas,-based travel company.

And until business travel demand picks up again, most airlines will continue to adjust their schedules. Analysts say that if the price of crude oil continues to go up — it's now trading at nearly $80 a barrel — domestic carriers may park even more airplanes in the desert. Industry analyst Mike Boyd said that if demand drops in the fourth quarter, American still has older aircraft that it can "park tomorrow if they have to."

He said domestic carriers are already running about as full as possible, as 100 percent load factors are statistically impossible because planes are often flown empty overnight to start their routes in the morning. And that has emboldened airlines to start increasing fares slightly.

For example, most carriers have added a $10 holiday travel surcharge for peak holiday travel days.

"You get anywhere past 85 percent, you are as full as you can get," Boyd said. "What that means is they have pricing traction. They can add a surcharge here or there."