WASHINGTON - US military jets have intercepted a small plane that strayed into restricted airspace around Washington, the second time in nearly two weeks fighter planes steered a wayward aircraft away from the capital with flares, aviation and military officials said.

Unlike the May 11 incident when the airspace breach prompted the evacuation of the White House, Capitol and Supreme Court, Monday's late afternoon incident triggered no frantic security response on the ground.

Senate leaders were notified Cessna had entered restricted airspace and were preparing to clear the floor when authorities sent word the plane had veered away from Washington.

Witnesses said the aircraft flew over the close-in Maryland suburbs shadowed by fighter jets, which dropped a flare to get the pilot's attention.

It was not clear if poor weather -- clouds and light rain -- were a factor in the incident.

An aviation source said the plane involved in Monday's incident was apparently on a flight from Knoxville, Tennessee, to the Washington area and "clipped" restricted airspace about 20 miles from Washington.

The source said the plane's pilot could not be raised on the radio but the reason for that problem was not clear.

Maj. Douglas Martin, a spokesman for the joint North American Air Defence Command, said two F-16 aircraft were scrambled from Andrews Air Force base outside Washington in Maryland.

Witnesses told Reuters the fighters dropped one flare at about 10pm GMT while flying approximately 10 miles north of downtown Washington in suburban Maryland.

Martin confirmed one flare was dropped to get the pilot's attention and said the pilot responded immediately and was directed to land at Gaithersburg, Maryland.

Separately on Monday, the Federal Aviation Administration said it had revoked the license of the pilot in charge of the plane that prompted the security panic 12 days ago, saying he "severely compromised safety and security."

Regulators said Hayden "Jim" Sheaffer did not adequately prepare for the flight and made numerous operational and judgment errors. A student pilot, Troy Martin, was at the controls of that plane, also a Cessna. Martin was not disciplined.

The FAA action was only the second license revocation in the past year for Washington airspace violations, which occur twice a day on average, regulators said. Other pilots have had licenses suspended for shorter periods.

Private planes, with rare exceptions, cannot fly within 16 miles of Washington and can only operate 30 miles beyond that if they electronically transmit a security code and maintain radio contact with controllers.

Sheaffer, of Lititz, Pennsylvania, can appeal to transportation safety officials or he can wait for a year and apply for a new license.

A lawyer representing Sheaffer did not return calls for comment.