Airlines claim Britain's airports could end up "gridlocked" over Easter because there aren't enough staff. 11 firms, including British Airways and Virgin Airlines, have have written to the Home Secretary warning of disruption to hundreds of thousands of passengers.
The UK Border Agency is under fire for a lack of staff able to carry out full security checks.
Virgin Airlines said: "After years of reducing frontline staff, returning to a 100% check system will mean lengthy queues at UK airports over critical holiday periods... If the Government wishes to continue with this policy, it must put the resource in place to make it possible."