British Airways has suspended flights to the Egyptian capital, Cairo, for seven days over security concerns.
BA alerted passengers booked on flights from Heathrow, which it runs once per day, and said: "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.
"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."
Lufthansa suspended flights yesterday, but resumed operations today.
The airline said in a statement: "As safety is the number one priority of Lufthansa, the airline temporarily suspended its flights to Cairo on July 20 as a precaution. Normal operations will resume Sunday and all flights are scheduled to operate."
A BA spokeswoman said customers who still wished to travel would be rebooked on flights with alternative airlines or offered a refund.
It is understood British Airways made the UK's Department for Transport aware of its decision ahead of the announcement.
The airline runs one flight from Heathrow to Cairo and back again per day.
Current British Foreign and Commonwealth Office (FCO) advice on travel to Egypt warns against "all travel" to certain parts of the country.
But Cairo is part of a safer region, where the FCO only suggests reviewing its advice before visiting.
Current advice warns against "all but essential" travel by air to Sharm el Sheikh.
That advice followed the bombing of a Russian airline which was brought down in 2015 shortly after leaving the Red Sea resort, killing 224 people.
One passenger said she was booked on a flight with BA on 25 and was alerted by text about the suspensions.
The IT worker, who is from Egypt and has lived with her family in Britain for six years, said she was supposed to meet her husband, children and other relatives.
"It's just terrible," she said. "It may seem like I'm just missing my flight for a holiday, but I really need to go."
Reuters reported it was told by three Egyptian airport security sources that British staff were checking security at the airport on Wednesday and Thursday.
BA was also among several major carriers to announce in June they would reroute flights to avoid the Strait of Hormuz.
The move, also taken by Australia's Qantas, Dutch carrier KLM, Emirates, Germany's Lufthansa, Malaysia Airlines and Singapore Airlines, followed the downing of a US drone by Iran.
Additional Reporting Reuters