Hundreds of British Airways passengers flew through the night from Gatwick to the Egyptian hub after the plane diverted halfway to Mauritius.
The Boeing 777 was due to take off from Gatwick at 7.38pm on Tuesday evening and fly 12 hours 6050 miles south of the Equator.
The plane was on a normal flight over France, Switzerland, Italy and the Mediterranean Sea before entering Egyptian airspace and flying near the Nile River.
But at 00:00 GMT, the plane turned around and flew in almost the same direction. The airline later said it was “due to a technical issue”.
Instead of arriving in the tropical Indian Ocean island of Mauritius on Wednesday morning, passengers returned to West Sussex Airport at 4.45am.
The flight schedule has been changed on Wednesday at 16.00. If it works as expected, passengers will be delayed by more than 20 hours.
At the other end of the route, hundreds of passengers await an unexpected extra day in Mauritius.
They were emailed: “Despite our best efforts, we have taken the difficult decision to delay your departure to London Gatwick overnight due to a technical issue with the departing aircraft.
“We do not underestimate the difficulties that this will cause. We are truly sorry for the change in your travel plans and we will do our best to help.
“Your new estimated departure time is 10:05 am local time on December 8th and will arrive at 6:25 pm on December 8th.
“You can claim reasonable overnight expenses for hotel accommodation, local transport and anything else necessary.
We also cover £20 for meals for adults, £10 for children under 12 and up to £25 for phone/internet use.”
The message did not mention the £520 compensation British Airways is required to pay each passenger for a delay of three hours or more due to a technical problem under European air passenger rights regulations.
A BA spokesman said: “Our pilots decided to return to Gatwick due to a minor technical issue and the aircraft landed normally.
“We apologize to our customers for any disruption to their journeys and our team has arranged for replacement aircraft to get everyone on their way as quickly as possible.”