Washington ? No guns in the cockpit, the Bush administration decided Tuesday, saying that pilots should concentrate on flying their airliners and let trained air marshals defend against possible terrorists.

Transportation Undersecretary John Magaw’s announcement was criticized by some lawmakers and the pilots’ unions, who said that they would try to overturn the decision.

Magaw told the Senate Commerce Committee that air marshals are better equipped to undergo the specialized training to safely handle guns on airplanes. The pilots, behind newly strengthened cockpit doors, can steer the aircraft to throw hijackers off balance and should have cameras installed so they can see what is happening in the cabin, he said.

“Pilots need to concentrate on flying the plane,” Magaw said. “My feeling is you secure the cockpit, and if something does happen on that plane, they really have to be in control of the aircraft. Pilots should not have firearms in the cockpit.”

Most flights do not have air marshals on board, though the Transportation Security Administration is hiring and training more.

Magaw said he was still deciding whether to allow nonlethal weapons, such as stun guns.

Flight attendant unions have been pushing for stun guns in the cabin, since pilots are no longer supposed to leave the cockpit to help quell a disturbance.

The airline security law passed following the Sept. 11 terrorist attacks gave Magaw the power to decide whether to arm pilots. But now some lawmakers want to overrule him. The House aviation subcommittee is scheduled to consider legislation on Thursday.