The government has insisted that tough new security measures will remain at UK airports for now, despite the growing anger of airlines and legal threats.
The new airport security measures are set to remain in place for now
Ryanair has threatened to sue if airport security measures are not restored to normal.
Virgin Atlantic is calling for a debate about who should bear the costs of tighter security measures.
The Department for Transport says the government does not believe it has to pay compensation under the law.
Budget airline Ryanair has issued a seven-day ultimatum to the government to restore airport security measures to normal or be sued for compensation.
The DfT said on Friday: "The security regime in place at UK airports is necessary because of the level of security threat and is kept under constant review.
"We have no intention of compromising security levels nor do we anticipate changing our requirements in the next seven days."
The DfT spokesman added that the restrictions were introduced under the Aviation Security Act of 1982, which allows the government to implement measures for the safety and protection of the public.
Ryanair has threatened to claim compensation under a different act - the provision of section 93 of the Transport Act 2000.
The measures the airline has demanded include:
Restoring the hand luggage allowance for passengers leaving British airports to the normal International Air Transport Association (IATA) dimensions of a small, wheeled case, which is just 20% larger than the current restriction of a "large briefcase" dimension
A return to the passenger body searches from the current one in two to the normal one in four.
The disruption to flight schedules because of the alleged bomb plot is estimated to have cost Ryanair up to £2m.
Margaret Moran, Labour MP for Luton South, which includes Luton Airport, says airlines should prepare for the cost of combating terrorism from now on.
"Airlines are having to, and the sensible ones are, reflecting on the fact that they will have to build in to their baseline, to their profit margin, the fact that we will always be on some kind of terrorist alert," she said.
Pilots who believe they should not be banned from taking liquids and gels into the cockpit have joined calls for the security measures to be re-examined.
BAA runs Heathrow and Gatwick, and five regional airports. The alert, which began on 10 August, sparked strict restrictions on airline baggage.
Passengers are able to take on board one piece of hand luggage which must not exceed 45cm x 35cm x 16cm (17.7ins x 13.7ins x 6.2ins) - equivalent to a small laptop bag or rucksack.
Twenty-three people are in custody in London, after being arrested in raids in London, High Wycombe in Buckinghamshire, and Birmingham last week.