Administration officials said Monday President Bush intends to reopen Reagan National Airport soon, just as Americans are slowly returning to the skies after the Sept. 11 terrorist attacks.

The officials cautioned that Bush had not made a final decision, but said a consensus had emerged among his inner circle that the airport, located outside Washington, needed to open as soon as possible. An announcement was expected as early as Tuesday.

Bush wants more security on planes and fewer flights at the airport. Changes would include placing air marshals on incoming and outgoing flights as well as limiting the number of planes using the airport, said senior advisers involved in the discussions. The Federal Aviation Administration would have to sign off on such changes.

Meanwhile, the Air Transport Association, a trade group for the major airlines, said that while air travel still is well below levels prior to the terrorist attacks, many more passengers flew on domestic flights this week compared to the previous week. 

Preliminary estimates showed 665,714 passengers flew on domestic flights Thursday, compared to 518,765 the Thursday before. The flights were 46 percent full, up from 39 percent a week earlier.

A year ago, airplanes carried around 1 million passengers a day and were around 70 percent full. There were no numbers on weekend flights, but airport and airline officials said it appeared more people were flying.

Monique Bond, a spokeswoman for the Chicago Department of Aviation, said there were longer lines at security checkpoints at both O'Hare and Midway airports.

"That's a good sign" Bond said. "Increased lines mean there are more travelers regaining their confidence in air travel."

Airline passengers are seeing greater security at airports and being encouraged to arrive two hours before departures. The National Guard has personnel patrolling major airports and more strenuous checks of passengers and baggage are being conducted everywhere.

Travelers at Los Angeles International Airport were forced to wait at shuttle depots and give up once-innocuous items such as nail files and clippers, but most took the new rules in stride.

Some said they were a little nervous about flying again, and also saw the tension in their fellow passengers. "Children were crying and everybody looked a little afraid," said Kerri Kubrick, 32, who was waiting at Los Angeles airport for a ride home to San Diego after a trip to Norfolk, Va.

Los Angeles Airport said officials have received relatively few complaints about the new inconveniences, but some of those complaints have been "pretty vociferous."

At least three airports — Dulles outside Washington, Houston's Bush Intercontinental and O'Hare in Chicago — are allowing passengers of certain airlines to check their baggage at the curbs, albeit under stricter security procedures.

Curbside check-in was banned when airports reopened following the attacks. Federal Aviation Administration spokesman William Shumann said the FAA now is approving requests from individual airlines and airports to allow curbside check-in if the tighter security measures are followed. He declined to identify the measures, citing security needs.

President Bush and members of his Cabinet have been encouraging Americans to return to the skies, saying it will help boost the economy and return some normalcy to lives disrupted by the terrorist attacks.

Top Bush aides met Monday with officials from Virginia, where the airport is located. They have urged the White House to reopen the airport, which is a major source of jobs in the Washington area.

National has remained shut because of its closeness to major government buildings and landmarks, including the White House, Capitol and Pentagon.

In addition to economic considerations, Bush considers reopening the airport a symbol of the nation's resolve not to bow to terrorism, aides said.

Reuters and the Associated Press cntributed to this report.