Aviation authorities in the US are moving forward with plans to shift towards a risk-based system of passenger screening - an idea supported by the travel industry and government officials who want screeners to focus on travellers who may present a security threat.
But as details emerge on how governments and airlines plan to distinguish between "trusted travellers" and those who will receive more scrutiny, civil liberties groups and some European regulators are questioning the use of personal data to decide which travellers to examine more closely.
Sharing information on passengers is at the heart of the new effort. The information governments use to vet passengers includes data individuals volunteer by applying for trusted traveller programs, as well as that gathered via terrorist watch lists, criminal background checks and customs encounters.
The risk-based approach extends to the list of items prohibited from the cabin, which the US Transportation Security Administration has revised to allow small pocketknives.
The government is also looking at data airlines and travel agents have collected on customers, ranging from birth dates and passport numbers to details apparent in itineraries (such as a flight to Pakistan) and group discount codes (for a trip to a conference, for instance).
For passengers on international flights, much of the data in these "passenger name records" is already shared with the US Department of Homeland Security.
The prospect of using passenger data for airport screening has exposed a fissure between more privacy-oriented European officials and their US counterparts.
Federal commissioner for data protection in Germany Peter Schaar told an aviation security conference in New York last week any system using passenger data to assess risk must be proved to be effective at rooting out terrorists, must be proportional without violating privacy rights and must avoid side effects like discrimination.
That perspective was in the minority at the event, organised by the International Air Transport Association and largely attended by screening equipment manufacturers, airline and airport security directors and government officials eager to move ahead with what they called the "passenger differentiation concept".
The US would also like to use more behaviour detection officers in security lines.
While airlines and equipment manufacturers are seeking similar security procedures worldwide, sharing travellers' data across borders presents complex challenges. Governments are debating how to recognise trusted visitors, and how to respond if nations such as China start asking for the same level of passenger data the US demands.
"The notion that the government is in any position to judge who is trusted and who is risky is very problematic," said Jay Stanley, from the American Civil Liberties Union. "Terrorist attacks on airlines are basically freak events ... so any attempt to predict who is likely to engage in that type of thing is inevitably going to sweep up a vast number of innocent people."