Airlines were today facing bad weather disruption in the face of storms across Europe following a record heatwave.
British Airways warned that “severe thunderstorms” had led to “significant delays and cancellations” to flights to and from London.
Heathrow tweeted last night: “Due to extreme weather conditions across Europe, Heathrow and other airport are experiencing delays and cancellations to flights.
“We’re very sorry for the disruption and advise you to contact your airline for more information.”
Passengers were reported to have been forced to sleep on the floor in Terminal 5 after flights were cancelled after long delays on Thursday night.
Many flights from Gatwick were facing delays or cancellations this morning.
This follows air traffic control restrictions which also affected flights using Stansted and Luton airports last night.
The situation was being compounded by a national air transport strike in Italy.
EasyJet said: “Like other airlines flying to and from Italy, easyJet expects an impact on its operations.
“We recommend to all customers departing from an Italian airport on Friday 26th July allow extra time to pass through airport security as queues may be longer than usual and for every passenger flying to or from Italy to check the status of their flight on our flight tracker either on our mobile app or website.
“Although this is outside of our control, we would like to apologise to customers for any inconvenience experienced and wish to assure them that we are doing everything possible to minimise any disruption as a result of this industrial action.”