Flights at Stansted Airport are expected to return to normal after a fire caused all departures to be cancelled on Friday evening.
Footage showed black smoke shrouding the terminal building when a shuttle bus burst into flames.
No-one was injured but passengers described an atmosphere of confusion in the aftermath as flight details disappeared from departure boards.
Airport bosses have advised passengers to check flights with their airlines.
The blaze at about 17:00 BST on Friday was caused by an electrical fault and destroyed the bus, which was parked in a waiting area.
It caused smoke damage to “much of the front of the terminal building,” firefighters said.
Later that evening Stansted Airport tweeted that all flights up until midnight were cancelled and passengers were asked to leave the airport.
But several passengers have described chaotic scenes inside the terminal after the fire was extinguished.
BBC journalist Stephen Fottrell was intending to fly to Ireland when he became caught up in the confusion.
“Once flights started to be cancelled they disappeared from the screen and we had a bizarre situation where the screens went blank. My flight came up as cancelled for just a couple of minutes and then it disappeared,” he said.
“People were going to the airline website checking their flights and all the information had gone from there too.”
Fottrell told BBC 5Live that in 18 years of regularly travelling from UK airports he had “never seen anything like it”.
“The level of confusion among people stood out – they just didn’t know what was happening,” he said.
“It was the usual situation of very few staff on the ground and they were doing their best but they were saying they didn’t work for the airlines.”
It was an experience shared by Taylor Fulton-Ward, 18, from Hertfordshire, who was flying to Dublin with her family for the Easter weekend.
She said: “We arrived at the airport and after a lot of waiting we got through security and staff told us all flights were running but delayed.
“After an hour, our flight disappeared from the board with no communication. We went back through to check in to try and re-book the flight but the crowds were crazy.
“Announcements were telling us to leave the building, but the doors were not open – so people began pushing and panicking.
“The biggest problem was not being able to get out the doors and a lack of communication.”
The airport said it will reopen with “flights expected to operate as normal”, although advised passengers to check with their airlines.
However, one of Stansted’s biggest carriers, Ryanair, earlier warned that traveller misery may extend into a second day of the Easter weekend.
Its most recent travel update said: “Unfortunately, further flight delays and cancellations are likely and customers are asked to please monitor this notice which will be updated throughout the day.
“We sincerely apologise for any delays or inconvenience caused by these disruptions which are outside of our control.”
Simon Calder, travel editor for The Independent, estimates that 15,000 travellers and 100 flights – to and from Stansted – were affected by Friday’s cancellations.
He told the BBC the problems stemmed from a decision to move people from the smoke-filled check-in area to the air-side zone beyond security.
“As a result of that, because they hadn’t been screened – because they were taken there in a hurry – no flights could depart until everyone was re-screened and the air-side area had been swept by security services to make sure no passengers had stayed behind.”
He said the whole process took so long that by 20:00 BST the airport and airlines agreed to shut down for the rest of the evening in the hope of minimising the impact on the following day’s flights.