Drink does it. Sex does it. But the real reason air rage is rising is 11 Sept

Air rage attacks, far from diminishing in the wake of 11 September, are likely to increase, according to a leading psychiatrist.

Airline passengers, filled with post-World Trade Centre attack anxiety, are now more likely than ever to lash out at fellow travellers and airline staff, warns Dr Graham Lucas, an adviser to the Civil Aviation Authority (CAA).

Despite a drop in passenger numbers of as much as 30 per cent in the past four months, air rage incidents have not reduced. Although no published figures exist, early indications from the CAA showed air rage incidents, post-11 September, were at a similar level despite fewer passengers. The previously published figures reveal 1,250 air rage incidents on UK airlines in the 12 months to last March.

This month Dr Lucas will tell a Royal Society of Medicine conference on the risks of international travel that "twitchy" passengers can now be expected to react to anything that seems out of the ordinary. Paradoxically, pre-emptive efforts to prevent terrorism could actually put safety in more jeopardy.

His claims are backed up by Islamic groups who have catalogued a list of recent air rage attacks on Muslims. One commentator said Muslims now fear going to the toilet on flights for fear of being "surrounded" by fellow passengers.

Dr Lucas, a consultant at the Priory Hospital Sturt in Surrey, who specialises in aviation psychiatry, said: "If there is a kerfuffle, passengers may well now suspect it's a terrorist incident rather than just some drunken person."

Professor Cary Cooper, a behavioural psychologist at University of Manchester Institute of Science and Technology, agreed incidents were now likely to rise. Passengers will now drink more on planes to quell increased anxieties. In almost half the officially recorded air rage cases, alcohol was "a contributory cause".

More importantly, passengers are now extra "sensitive" to anything they perceive as unusual on a flight.

"The bigger increase will be from passengers who are suspicious of behaviour of other people on a plane and will confront them," says Prof Cooper, "My real fear is anybody who behaves in a strange way on a plane is now at risk of attack."

Even the most innocuous may be targeted – especially if they are Arab or Asian. Muslim News has begun a database of Islamaphobic attacks since 11 September, charting six assaults, either physical or verbal, so far.

Many more attacks, reckons its editor Ahmed Versi, have gone unreported.

Murtaza Walji, a father of two from Birmingham, was flying from New York to Seattle recently when a passenger behind him became extremely loud and abusive.

"She was shouting at me. Maybe she was scared but she was blaming me for what had happened in New York," recalled Mr Walji, 44. "There were a lot of people on the plane but I was the only Asian." At the end of the flight, the woman even called security and police, who stopped Mr Walji as he got off the plane.