Travellers to the US face delays after more rigorous security checks were implemented by the authorities.
Airlines are advising customers to arrive early for flights and some have taken on extra staff to question passengers during check in.
The additional security screening has been ordered by US president Donald Trump and could involve questioning and inspection of electronic devises like phones and laptops.
The policy could affect some 325,000 airline passengers on about 2,100 commercial flights arriving daily in the US on 180 airlines from 280 airports in 105 countries.
The new rules are being applied to all passengers and were put in place after plans to ban laptops in aircraft cabins was ditched.
British Airways told The Times its flights would continue to operate as normal. “The safety and security of our customers is always our top priority,” a spokeswoman said.
Air France has brought in a new questionnaire and will conduct security interviews at Charles de Gaulle. Lufhansa Group said its customers may also face a short interview at check -n.
Cathay Pacific has suspended self-checked baggage services and Virgin Atlantic is advising customers to arrive two hours before take off while Delta and Continental are saying three hours.
Virgin Atlantic said: “We work closely with US authorities to ensure the safety and security of our flights, and are aware of the additional measures. However, we do not anticipate any disruption to customers.”