Nerves tested by flight security on everyone's mind

The events of 11 September have prompted a rash of security alerts across the airline industry, ranging from understandable alarms to hyper- sensitive reactions and in some cases utterly stupid behaviour.

The events of 11 September have prompted a rash of security alerts across the airline industry, ranging from understandable alarms to hyper- sensitive reactions and in some cases utterly stupid behaviour.

They include a police inspector who was barred from a flight to Crete after he joked to security staff at Manchester airport that he had a bomb in his bag. Police were called and although the motorway patrol officer apologised he was not allowed to board the aeroplane and now faces an investigation by Greater Manchester Police.

An Air Canada aeroplane heading for Toronto returned to Los Angeles with an escort of two US Air Force F-16 fighter jets after a passenger became unruly when he was told to stop smoking in the lavatory. The air crew subdued him but the pilot made the decision to fly back to the departure airport. An airline spokesman said the hijackings had "some bearing" on the pilot's decision.

Police had to intervene when a Northwest Airlines pilot became enraged after airport security confiscated his fingernail clippers and scissors before he boarded a flight at Rapid City, Dakota. The flight departed with the pilot at the controls.

A plane was held on the runway at Dulles airport in Washington after a Saudi Arabian pilot asked to sit in the cockpit, a privilege extended to other pilots before 11 September. Despite the FBI saying the man was no threat, the crew insisted he be transferred to another flight, while many passengers refused to fly with him on board.

Also at Dulles, a flight attendant on a Northwest Airlines flight bound for Amsterdam became suspicious about a passenger and telephoned a friend. The friend called the FBI, who then called the airport, which sent agents and police to board and surround the plane.

The two pilots and a flight engineer then escaped from their cockpit on rope ladders. The flight eventually took off after 23 hours' delay and no threat was discovered.

At Logan airport in Boston 500 people were evacuated from 11 flights after a security guard recalled seeing a knife in a bag as it went through an X-ray machine, but did not bother to examine the bag by hand.

A 59-year-old American businessman was arrested with four box-cutting knives, similar to the ones used by the hijackers, when he tried to board a flight from Philadelphia to Minneapolis. He said he took the knives on board to show his wife and America how it was still easy.

He has since been barred from flying.

Nearly 100 passengers were cleared from a flight at Aberdeen airport minutes before it was due to take off when the flight crew spotted air pistols in the luggage of a party of Norwegian schoolchildren.