Airlines could screen passengers at check-in
This is where airlines use passenger profiling to identify people who, on grounds of such things as conduct or appearance, they believe could pose a risk to security.
They then subject them to more questioning or greater surveillance.
But it is a controversial practice that critics say unfairly targets minorities.
Chris Yates, aviation security editor at Jane's Transport, told BBC Radio 4's Today programme a certain amount of screening already took place in the UK.
"There has been an awful lot of debate about so-called profiling of passengers - identifying people based on ethnic origin and so on and so forth.
"Profiling does take place in airports - it's based in general terms on your prior travel history, but the other factors I'm afraid are not included in that profile, for very obvious reasons."
Shadow home secretary Oliver Letwin said any kind of passenger profiling raised big questions about human rights and discrimination.
"I wouldn't like to see groups of people segregated as one goes through the departure lounge because they happen to come from whatever is that month's risk category - being deeply frisked in the way that everyone else isn't.
"I'm afraid we're going to have to live with the fact that all of us are going to be subject to greater security measures in order to avoid that kind of discrimination."
Confidential criteria
Other countries use varying amounts of passenger profiling - but the criteria used is always kept strictly confidential.
Israel's national carrier El Al - famous for having the strictest security measures in the world - has profilers who question passengers before they board to try to detect would-be hijackers from their behaviour and answers.
In the US there is an automated profiling system, Computer Assisted Passenger Pre-Screening (CAPPS).
This is a database of information about passengers collated from the airline's reservation system, which then determines whether the passenger is a "selectee" or a "non-selectee" for heightened security checks.
The Federal Aviation Administration insists this does not target any group based on race, national origin or religion.
But there have been complaints that Arab Americans and Muslims have been disproportionately selected by the system.
British system
British pilots have backed a similarly computerised passenger screening system, called MatchMaker, which checks passport details against a database of suspects.
Qinetiq, the company which is developing the system, says it would hold data "that uniquely identifies passengers who are of interest to the authorities or have been disruptive on previous airline flights".
It says the details could be fed in by governments, airlines, police forces and other agencies.
Ian Hibberd, of the British Airline Pilots Association (Balpa), has strongly backed the system.
"The place to stop would-be terrorists or disruptive passengers is on the ground, not in the air.
"The Matchmaker system can significantly improve air safety," he said.