Multiple airlines have temporarily suspended flights in and out of Cairo, following an ongoing security review.
British Airways has announced it has suspended flights to Cairo for seven days as a precautionary measure following a security review.
And German carrier Lufthansa is also temporarily stopping services to the city for at least 24 hours.
British Airways said it would not operate its aircraft unless it felt it was safe to do so.
"We constantly review our security arrangements at all our airports around the world, and have suspended flights to Cairo for seven days as a precaution to allow for further assessment," British Airways said in a statement.
"The safety and security of our customers and crew is always our priority, and we would never operate an aircraft unless it was safe to do so."
German carrier Lufthansa said it was suspending flights to Cairo from Munich and Frankfurt without giving any reason.
A Lufthansa spokesman said normal service should return in a day. The British flag carrier said it would not operate its aircraft unless it felt it was safe to do so.
Egypt's civil aviation ministry said it was "co-ordinating" with the British embassy in Cairo and the local BA representative and starting an extra EgyptAir flight to London every day to carry stranded passengers.
Some affected passengers posted pictures on social media appearing to show a letter handed out by BA with a similar message.
A spokeswoman for the airline said it could not immediately offer more information about the suspensions.
In its travel advice for British nationals heading to Egypt, the Foreign Office in London warns: "There's a heightened risk of terrorism against aviation".
"Additional security measures are in place for flights departing from Egypt to the UK. You should co-operate fully with security officials at airports." Britain advises against all but essential travel by air to or from the Red Sea resort of Sharm el-Sheikh on the Sinai Peninsula.
"Terrorists are very likely to try to carry out attacks in Egypt. Although most attacks occur in North Sinai, there is a risk of terrorist attacks across the country," Britons are warned.
"Terrorists in Egypt likely maintain the intent and capability to target aviation.
"The greatest threat is on the Sinai Peninsula where Daesh operate with greater freedom, but terrorists are active in mainland Egypt, including Cairo." The Foreign Office warns that it "can't offer advice on the safety of individual airlines".
An estimated 415,000 British nationals visited Egypt in 2018. Britain cancelled flights to Egypt's Sharm el-Sheikh in 2015 after jihadists bombed a Russian airliner carrying holiday-makers from the Red Sea resort, killing more than 220 people on board.