One is lucky enough to find a seat on a U.S. domestic flight these days, and come autumn, industry observers say not to expect much elbow room.

Major U.S. airlines announced Tuesday they would limit available seats to reduce their costs while driving up ticket prices. Airline stocks went up following the announcement.

"There are some days on some flights when there are simply no physical seats left," says Jim Reichart, vice president of marketing and sales for Frontier, which sold 91 percent of its seats in July and August.

An Associated Press analysis of preliminary data reported by 16 major U.S. airlines shows that paying customers' occupancy was at 86.4 percent overall in July and August. Last summer's record was 86.3 percent.

The Associated Press reported Frontier and US Airways both had their best August for percentage of seats filled.

It is business as usual, as consolidation, partnerships and necessary elimination of unprofitable routes make airlines adjust schedules to match demand and charge more.

Even as most airlines have taken away hot meals, blankets and headphones from domestic flights, people are flying nonetheless, albeit with frustration over their discomfort. This summer there were 130 million domestic trips in the U.S., airline say.

"In the past we had the problem of people operating airlines based on ego," says airline consultant Michael Boyd. "Now they're operating on the basis on how much money they can make."

Analysts say there could be more space this autumn, but not much, if the economy continues on a sour path. This means flights around Thanksgiving and Christmas should have been booked ahead or there will be armrest wars.

All the major airlines except American have made money this year. United charged about 8 percent more for each seat in July than last year, and 11 percent more in August.

Meanwhile, Allegiant Air, which flies vacationers from small U.S. cities to tourist destinations, was 93 percent full this summer. This autumn, it plans to reduce available seats by almost a third, says Jude Bricker, the airline's treasurer.

Until 1978, regulation limited airline competition, allowing companies to be profitable even when planes were not full. In the early 1970s, about half of seats were sold. Ten years following deregulation, airlines sold about 60 percent of seats. This increased over the decades. In 2008, amid high fuel costs and falling demand due to a recession, airlines ceased hundreds of unprofitable flights.