UPDATED: 15.35pm FURIOUS airlines and tour operators have lashed out at airport owners and the government as passengers endure a sixth day of delays and cancellations.

Ryanair said BAA's failure to adequately staff Stansted, combined with "nonsensical" new hand baggage restrictions, had "paralysed" the airport early this morning.

"This issue continues to cause flight delays and currently, BAA Stansted have been unable to confirm their staffing levels for this evening and tomorrow, so we are anticipating that flight delays and cancellations will continue," a Ryanair statement said.

"These problems will continue until the UK government leads a return to normality at London airports.

"Ryanair continues to urge the UK government to defeat these extremists by returning UK air travel to normal, as they successfully did on the London Underground within 2 days of last year's 7/7 attacks."

Ryanair called on the government to send in extra army or police officers to help with the security checks.

The cut-price Irish airline also questioned why liquids had been banned on flights, but not on the London Underground or the Eurotunnel.

British Airways has already cancelled 40 short-haul and four long-haul flights from Heathrow today and 11 domestic flights from Gatwick, while Ryanair has cancelled eight flights from Stansted.

BA, Virgin Atlantic and easyJet have reportedly united to call on BAA to compensate them some of the £250m they've lost during the terror crisis.

BA chief executive Willie Walsh told the Daily Mirror that the airline may sue BAA.

"Since 9/11, everyone in the industry has known there might be times when extra security measures needed to be put in place. Yet when the moment struck, BAA had no plan ready to keep Heathrow functioning properly," he said.

"The queues for security have wound all round the terminals like a bad dream at Disneyland."

The Federation of Tour Operators called for an independent inquiry into the handling of the crisis by the government and the British Airport Authority, which owns Heathrow, Gatwick and Stansted.

FTO Chairman Ian Ailles said inconsistent airport policies, clearly inadequate staffing arrangements and a lack of rehearsed contingency planning have made the situation far worse for travellers than it needed to be.

"It is not clear to us how airport security arrangements at times of heightened tension have improved in the five years since the 9/11 tragedy," he said.

"We call a for an independent inquiry, in the weeks to come, of the handling of this crisis by all the parties involved - especially the airports and the government's own planning for passenger security in the light of this long-recognised potential threat."

Meanwhile, it's been reported that transport chiefs were considering "passenger profiling".

The Times reported that passengers who were behaving suspiciously, have an unusual travel pattern or have a certain ethnic or religious background could be selected for extra security checks.

It's hoped the profiling would greatly reduce queues at security gates.

BAA had hoped today's new measures would end the travel misery passengers have had to endure since the alleged plot to blow up transatalantic planes was foiled last Thursday.

The relaxed restrictions were introduced at Stansted yesterday and came into force at Heathrow and Gatwick at 4am this morning.

BAA said punctuality was improving, but the new measures was not a return to normal and warned anyone travelling over the next few days to allow extra time for their journey and to arrive at the airport prepared.

Under the new rules, passengers can take on board one small cabin bag, but liquids remain banned.

Click here for the BAA airport security flyer

Eased airport security measures:

  • Each passenger is permitted to carry one item of cabin baggage through the airport security search point. The dimensions of this item must not exceed: a maximum length of 45 cm, width of 35 cm and depth of 16 cm (17.7"13.7"6.2" approx) (including wheels, handles, side pockets etc.).
  • The bag must NOT contain:

- Any liquids, cosmetics or toiletries, including gels, pastes, lotions, liquid/solid mixtures, perfumes and the contents of pressurised containers - these must be checked in as hold baggage.- Cigarette lighters are NOT permitted in hold baggage or through the security search. These may be purchased airside.

  • The bag CAN include:

- Electronic equipment including mobile phones, digital cameras and MP3 players (such as iPods).- Prescription medicines in liquid form, eg diabetic kit.- Baby milk and liquid baby food (the contents of each bottle MUST be tasted by the accompanying passenger). - Laptops must be removed from the bag for x-ray.

  • All remaining items in pockets should be placed in the clear plastic bag provided, eg car keys and fobs, cash, solid food, books, newspapers, cigarettes and tobacco.
  • Pushchairs and walking aids are permitted but must be x-ray screened. All wheelchairs will be subject to search. Please note: You may be subject to a hand search by the security team and required to remove footwear to be x-ray screened.
  • Once in the departure lounge passengers may purchase any item in any store and take it onto the aircraft as normal unless you are travelling to the USA.