Following the failed bomb attack on a flight from Amsterdam to Detroit on Christmas Day, the UK government has said it will do everything in its power to tighten security at its airports.
What new checks will passengers face?
The most significant development will be the arrival of new full body scanners at airports, to be gradually introduced after getting the go-ahead from Prime Minister Gordon Brown.
The "passive millimetre wave scanners" remove the need for pat-down searches of travellers.
The full body scanner could spot hidden items like explosives or drugs
Passengers stand in a booth to have electromagnetic waves beamed at them, with the reflected energy used to create a virtual three-dimensional image.
The machines will initially operate alongside the familiar existing metal detectors, for checks on flights in and out of the UK.
BAA, which runs six UK airports, says the devices will be introduced at Heathrow "as soon as practical".
The Department for Transport (DfT) says it is "consulting urgently with the airport industry on how they might best be introduced at other UK airports".
The DfT also said there would be increased use of existing security measures, including swabs of hand luggage for explosives traces and deployment of sniffer dogs.
After the failed attack on the US, are there special measures for flights there?
New tougher screening rules for flights to the US mainly apply to 14 countries deemed by America to have links to terrorism.
The UK is not one of those countries, but travellers bound for the US from anywhere could face random extra checks under the measures.
However, the introduction of the measures related to US flights on Monday caused no serious disruption at UK airports, according to the DfT.
Does that mean travellers can leave for the airport as normal to catch a flight?
Actually, the DfT advises allowing plenty of extra time for checking in at the moment.
The department's usual advice is three hours for long-haul flights, two hours for European flights, and 90 minutes for domestic journeys.
Passengers should check their airline's advice on how long to allow, and for details of any of their operator's own security guidelines, the department says.
Virgin Atlantic recommends getting to the airport three hours before departure on flights to the US, and to go straight through security immediately after checking in.
British Airways (BA) advises passengers to check the status of their flight before leaving for the airport.
Are airlines implementing different security measures?
The DfT says these measures can vary from airline to airline.
In response to the new US security changes, BA says passengers are only allowed one item of hand luggage on its flights to the US from Heathrow, Gatwick and London City.
This applies to people whose journey originates at those airports, as well as those transferring flights.
The BA website advises that passengers will be able to check in extra bags they had been intending to carry on to their flight free of charge, but the items must conform to hand baggage size and weight limits.
Will the arrival of the full body scanners increase disruption?
Use of scanners installed at some major airports overseas has been limited owing to concerns over costs and delays.
Gordon Brown has said he hopes tighter UK security arrangements will not cause too many delays for passengers.
Manchester airport, which has been trialling one of the full body scanners since last October, has suggested security checks will be speeded up by the machines' use.
Passengers were not required to remove coats, shoes and belts for the scanner, and also avoided the unpopular "pat down" search, an airport spokeswoman said.
"The scanner completely takes away the hassle of needing to undress," she said.