Some passengers had to fly from Heathrow without their luggage today after a power cut affected Terminal 5.
The airport said it was working hard to reunite passengers with their bags as quickly as possible.
Marcel Maier, 35, travelling to Hamburg, told The Mirror: "The queues are long and chaotic, but I've just had to leave my baggage with the staff and hope that it arrives.
"I am not confident it will arrive today, the airport isn't sure either, so that is definitely going to cause me frustration.
"People are really frustrated, and it's crazy just looking at the piles and piles of bags everywhere."
The power cut happened between about 7am and 10am.
A spokesman for the airport said: "This morning Terminal 5 suffered a loss of power due to an issue with our supplier. Power has now been restored, however the baggage system has been impacted. We apologise and are working hard to resume a full service, and reunite passengers with their bags as quickly as possible. Flights are continuing to operate as normal."
A spokesman for British Airways said: "Heathrow's baggage system in T5 experienced difficulties today due to an earlier power outage in the terminal.
"Heathrow Airport is working hard to restore a full baggage system. We are sorry for the delays this has caused and are doing everything we can to maintain our normal baggage services.
"Where we were unable to get bags on to the same flights as customers we will put them on to the next flight and courier them to customers as soon as possible free of charge.
"All flights are continuing to operate as normal."