WASHINGTON (AP) President Bush will announce an expanded role for National Guard troops at airports, possibly stationing them at boarding gates, administration officials said yesterday.

An announcement is expected today at a White House ceremony honoring private-sector employers of guardsmen and reservists, said the officials, speaking on condition of anonymity.

The plan calls for a "dramatic increase" in troops at airports, one official said.

Bush"s announcement, ahead of the busy holiday travel season, was intended to increase confidence in air travel while Congress works to finish an airline security bill, one source said. It will take months to put any changes into effect even once a compromise bill passes.

Governors have used guard members at security checkpoints, where passengers and carry-on baggage are screened, as well as for general patrol duty at airports.

One idea under review by the president would have guardsmen monitor passengers who have gone through security and are in the boarding process.

Recent security lapses have shown that current measures are not foolproof: Last week at Chicago"s O"Hare Airport, a gate search by airline employees of passenger who had gone through security found seven knives, a stun gun and tear gas.

The president asked governors in September to station guardsmen for as long as six months at the nation"s 420 commercial airports, with the federal government to cover the cost.

It was not immediately clear whether Bush would again ask the governors to call up troops or act on his own.

The idea of using guardsmen to screen travelers drew a skeptical response from David Stempler, president of the Air Travelers Association, an advocacy group.

"I don"t know what part they have to play in the security process other than to have a show of force," he said.

Also yesterday, major airlines announced they have finished installing bars, latches and other equipment to strengthen cockpit doors steps to prevent hijackers from getting into cockpits, as they did Sept. 11.

"This is so crucial as we go into the holiday season," said Carol Hallett, president of Air Transport Association, which represents the major airlines that carry 97 percent of passengers. "Americans across the board can have full confidence."

An annual AAA survey for Thanksgiving travel forecast 4.6 million people traveling by air, a 27 percent decline from last year"s 6.3 million. That translates to 13 percent of the 34.6 million people expected to travel 50 miles or more from home, compared with 17 percent in 2000. On other hand, 87 percent will travel by car, the highest percentage recorded by AAA and up from 83 percent last year.

Transportation Secretary Norman Mineta ordered airlines in early October to strengthen the doors. The Federal Aviation Administration allowed airlines to move ahead without following normal requirements for modifying planes.