Travellers have been warned that flights could be delayed or cancelled following a technical issue at Heathrow Airport.
Britain's air hub said early on Wednesday morning that a lighting issue had affected both runways.
The runways have now re-opened, however technicians are continuing to monitor the situation.
Passengers have been advised to check their flight status prior to travelling.
Heathrow tweeted that the problem had been resolved by 6.05am.
The issue left some London-bound passengers stranded on the tarmac in the US, although British Airways made their waits easier with snacks and drinks.
"On the ground in Atlanta due to Heathrow light failure. The bar is open and I'm not working tomorrow so not that fussed," passenger Davey Hunt wrote on Twitter.
Other passengers were less patient as they waited for updates from BA staff.
"We are on BA116 and ground staff at JFK Airport not opening the door so we can talk to someone. Pilot growing impatient as are passengers," Twitter user Shaan Khan wrote.
Nearly one in seven flights due to land at Heathrow between 6am and 8.59am were delayed, affecting 16 flights, according to aviation data firm FlightStats.
Out of 22 scheduled departures between 6am and 6.59am there was one cancellation and two flights delayed.
A spokeswoman for British Airways said: "There was an issue with Heathrow Airport's airfield lighting during the night.
"Contingency plans were quickly activated and we plan to operate our full schedule today, albeit with some delays.
"We're asking customers that are due to travel with us today to continue to monitor ba.com for any updates to their flight."