New security measures that require all passengers leaving British airports to undergo a body search are not sustainable and need to be reviewed Ryanair ceo Michael O'Leary said today.
After a day of cancellations he said the security services at Heathrow, Gatwick and Stansted could not cope.
"Ryanair and other major UK airlines cannot keep cancelling flights and disrupting the travel plans of tens of thousands of British passengers and visitors solely because the BAA cannot cope with the new body search requirements," he said.
Ryanair today called the Government security measures "heavy-handed" and urged them to be revised.
In a statement, the company said some did not enhance protection, but disrupted the journeys of thousands of British passengers and visitors, and were bringing the main London airports to the point of collapse.
The company said it supported "all sensible and effective security measures", but they should be targeted towards the flights at risk or groups that posed a threat, adding: "If the main UK airlines are forced to continue to cancel flights because the airports cannot meet these security requirements then the extremists will have succeeded."
Mr O'Leary said: "The goal of these terrorists and extremists is not just to kill but also to disrupt the economic life of Britain.
"The UK Government, by insisting on these heavy-handed security measures, is allowing the extremists to achieve many of their objectives.
"It is vital that the Government works with the UK airports and airlines to prevent the collapse of the London airports. We believe that the body search requirement can and should be revised from 100 per cent to the normal 25 per cent of passengers without in any way diminishing airport security.
"These numbers still allow any suspect groups or routes or individuals to be body searched. More importantly they will allow the main UK airports and the UK air transport system to return to normal which is the most important message we can send to these extremists."
He added: "Britain must not be beaten by extremists. We must not be terrorised and we cannot allow our economic life to be disrupted.
"The Government must act today otherwise these extremists will have succeeded by disrupting the economic life of Britain, its air transport industry and its citizens. We must not allow these terrorists to succeed."
The airline operator said the remaining flights were expected to depart from the airport on time or with as little delay as possible.
In a statement the British Airports Authority said: "BAA sincerely regrets this disruption and thanks passengers for their patience.
"Passengers are urged to check with their airlines before travelling to the airport." A BA spokeswoman said it had cancelled 30 per cent of its flights in and out of Heathrow today.
She added that all 23 domestic flights to and from Gatwick today had been cancelled, excluding flights to Jersey.
Paul Charles, director of communications at Virgin Atlantic, said it was "supportive of BAA because they are having to do a very difficult job in extreme circumstances".
Likewise, low-cost airline easyJet praised BAA, saying its services were back to business with no "unusual delays" or cancellations yesterday.
But BAA's chief executive officer for Heathrow, Tony Douglas, blamed the measures themselves, saying they were "not sustainable".
"If this is maintained we are likely to continue to see extremely long queues and regrettably even more flights cancelled.