The budget airline Ryanair today issued the Government with a seven-day "ultimatum" to restore airport security measures to normal levels or risk being sued for compensation.
The request for a return to usual security was made by the Irish no-frills carrier to Transport Secretary Douglas Alexander.
Ryanair said that if security was restored to normal International Air Transport Association (IATA) levels within the next seven days then the airline would "not make any claim for compensation which it is entitled to under the provision of section 93 of the Transport Act 2000".
Ryanair chief executive Michael O'Leary said today: "The best way to defeat terrorists and extremists is for ordinary people to continue to live their lives as normal. Because of the additional security restrictions imposed by the Government last Thursday, the shambles at the London airports has been anything but normal.
"The UK Government successfully led the return to normality of the London Underground within two days of the July 7 terrorist attacks. It is important that they now restore security at the London airports to normality and remove some of these nonsensical, and (from a security perspective) totally ineffective restrictions which were introduced last week.
"If they don't, and if they allow these restrictions to stay in place, then the Government will have handed the extremists an enormous PR victory."
Ryanair said the measures it was asking for involve:
:: Restoring the hand luggage allowance for passengers leaving British airports to the normal IATA dimensions of a small, wheeled case, which is just 20% larger than the current restriction of a "large briefcase" dimension. "There is no difference in security whatsoever between a large briefcase and a small carry-on wheelie bag", the airline said.
:: Returning the passenger body searches from the current one in two to the normal one in four, which still allows any suspect passengers to be individually body-searched. This will reduce the pressure on security staff as well as eliminating the queues and delays at British airports' security points, it added.
:: Ryanair has also asked for the Transport Secretary's assurance that the next time the Government quadruples the number of individual body searches, it will send in police and Army reserve personnel to help carry out these additional searches.
"This will at least allow the increased security to be carried out, in an emergency, without the disruptions, delays and cancellations that have characterised the chaos at London airports over the past week," the airline said.
Ryanair said that while airports and schedules had returned to normal in recent days, this was mainly due to "emergency rosters and overtime being operated by airport security staff".
The airline went on: "The extraordinary efforts of these people are not sustainable and the only way to prove to the terrorists that they cannot disrupt British life is to return the airport security requirements to their safe pre-August 10 levels."
Ryanair also announced today that in order to "get Britain flying again" it was releasing one million seats for sale on more than 100 routes, priced at £25 one way including all taxes and charges.
Mr O'Leary said that by doing this, the low-fare airline was "playing its part to encourage British people to keep flying, and more importantly, encourage British visitors to come to London, which is the best message we can send to the extremists, namely that we will not allow the economic life of Britain to be disrupted by their mindless and senseless activities".
Paul Charles, director of corporate communications at Virgin Atlantic Airways, said today that Virgin was in discussion with airport operator BAA about possible compensation.
Mr Charles went on: "We are not seeking compensation from the Government, but we think the Government should pay for extra security at airports.
"The threat is against the UK, and in the same way that the Government pays British Transport Police to patrol the railways, the Government should pay for airport security."
Separately, Virgin today called for a Competition Commission inquiry into the running of British airports in a submission to the Office of Fair Trading.
Mr Charles said: "We are saying that this is a complicated market and it's time that an independent body looked at what should happen at airports."