The Federal Aviation Administration late yesterday ordered U.S. airlines to intensify the screening of passengers, baggage and cargo on selected flights as part of a beefed-up program of airport and airline security in reaction to terrorist bombings and hijackings.

The order requires a "visible increase in physical inspection" for carry-on items that have passed through X-ray machines and a match of luggage identification tags and passenger names. Freight and cargo, including mail, will have to be held for 24 hours or physically inspected or X-rayed, the order said.

The order also abolishes curbside baggage check-in for all international flights.

The flights that would receive special attention would be designated by the FAA based on unpublished criteria. Most of those flights would be international, sources said, but some domestic flights would also be included. "It's likely to take longer to board international flights than it does now," a senior department official said.

The airlines were asked to impose the controls immediately on a voluntary basis. The FAA will follow that request with a formal amendment to mandatory airline operating instructions.

The order is the first announced step in a major Transportation Department program aimed at increasing airline and airport security. The department has also asked President Reagan for an expanded air marshals program and more research and development money for a system to detect explosives in baggage.

The FAA action came as the administration and Congress moved to capture the offensive in improving security for U.S. air travelers, especially those on international flights.

The House Foreign Affairs Committee unanimously approved legislation that would require the president to order boycotts of all international airports that do not meet U.S. security guidelines and to cut off foreign aid to the countries where they are located. The bill also requires the president to deny entry into the United States of airlines from countries with unsafe airports.

Another proposal that would blacklist airports has already passed the full House and the Senate Commerce Committee is planning hearings Thursday on several Senate proposals offering a variety of solutions to the problem.

Under the House Foreign Affairs Committee proposal, the secretary of state would have six months to publish a list of airports that do not meet U.S. security standards. If the airport does not meet the standards within 120 days, the president would be required to prohibit U.S. carriers from flying there and that country's airlines from flying to the United States.

The president could waive those actions for national security or humanitarian reasons.

Matthew V. Scocozza, assistant transportation secretary for policy and international affairs, said any proposal mandating boycotts might hamper the president's conduct of foreign policy. But he conceded that the waiver would "give the president more flexibility."

Rep. Dante B. Fascell (D-Fla.), committee chairman, said the legislation "puts the responsibility right where it belongs, and that is on the administration."

An amendment proposed by Rep. Tom Lantos (D-Calif.) allows the president to order boycotts of airlines using airports not under the control of a government, an attempt to close the airport at Beirut.

Officials from the International Federation of Air Line Pilot Associations, the International Air Transport Association and the administration told the committee that they opposed provisions that would require the government to publicize airports with inadequate security.