WASHINGTON — Ahead of the holiday travel crunch, President Bush ordered steps today to reduce air traffic congestion and long delays that have left passengers stranded.

The most significant change is that the Pentagon will open unused military airspace from Florida to Maine to create “a Thanksgiving express lane” for commercial airliners. It will be open next week for five days — Wednesday through Sunday — for the busiest days of Thanksgiving travel.

Mr. Bush said the problems with delayed flights are “clear to anybody who’s been traveling. Airports are very crowded. Travelers are being stranded and flights are delayed, sometimes with a full load of passengers sitting on the runway for hours.

“These failures carry some real costs for the country, not just in the inconvenience they cause but in the business they obstruct and the family gatherings they cause people to miss,” the president said. “We can do better.”

The new plan also will be in effect for the Christmas travel season, and a White House spokeswoman, Dana Perino, said the Federal Aviation Administration was imposing a holiday moratorium on nonessential maintenance projects, allowing all FAA personnel and equipment to be focused on keeping flights on time.

Further, the Department of Transportation will propose doubling the bump fee that airlines must pay to travelers who buy tickets but wind up without a seat. The penalty now is $200 or $400, depending on long the passenger has been inconvenienced. The proposed increase would make the fee $400 to $800. Ms. Perino said that rule, if it becomes final, wouldn’t be in place until next summer’s travel season.

Further, officials said the FAA would take other steps to increase efficiency such as rerouting airspace, using technology to fill unused space in the air and on the ground, and using more precise routes for takeoffs and landings.

Another proposed rule would deem the operation of a chronically delayed flight — defined as a flight that operates more than 15 minutes late more than 70% of the time — to be an “unfair and deceptive practice.” That designation carries with it substantial monetary penalties.

The president said other steps were under consideration to reduce crowded skies, such as charging airlines higher landing and takeoff fees at peak hours, and auctioning off landing and takeoff rights to the highest bidder.

Domestic carriers are expected to fly roughly 27 million passengers worldwide over 12 days beginning November 16, with planes about 90% full, according to the Air Transport Association.