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.