Hundreds of Belfast-bound passengers were stranded in London overnight as thunderstorms affected flight schedules and caused several cancellations.
Easyjet cancelled two flights from Gatwick to Belfast International Airport on Friday evening.
The firm said delays caused by the weather meant flight crews had reached their working hours limit.
Several airlines were affected and London hotel rooms filled up quickly, meaning some had to sleep in airports.
A spokeswoman for Gatwick Airport said severe weather across the London area, coupled by storms in continental Europe, had affected both the inbound and outbound schedules.
She said decisions that affected services were taken in the interests of passenger safety.
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Among the passengers affected was Jim Flanagan, the former editor of the Ballymena Guardian newspaper.
Mr Flanagan and his wife were due to travel home on the 19:05 BST Easyjet flight from Gatwick on Friday night.
He told BBC News NI that the flight had been delayed by three hours, and then, as passengers were standing on the tarmac waiting to board the plane they were told the flight had been cancelled.
The couple were visiting their son in Brighton and were able to stay with him for the night, but Mr Flanagan said he felt very sorry for families with young children who were upset as they had no accommodation.
He added that he could not book another flight online as Easyjet's website "kept crashing".
Mr Flanagan said eventually got through to the airline by phone on Saturday morning and the first flight they offered was late on Sunday.
He claimed there were "massive question marks over customer services".
Another passenger, who was meant to board the same flight, told BBC News NI that she had missed her mother's birthday celebration in Ballymena.
"The flight had been delayed by three hours and we were literally about to get on board when we were told it was cancelled," she said.
"I was gobsmacked. I was stuck at the airport until three in the morning. It was horrible.
"So many people were just lying on floors. There were so many cancellations and delays. There was a huge queue at the help desk".
On Saturday morning, the woman was contacted by Easyjet and offered a full refund or alternative flights.
In a statement to BBC News NI, an Easyjet spokesman confirmed that flights EZY839 and 841 from London Gatwick to Belfast on 10 August were cancelled "due to crew getting out of hours as a result of earlier delays at the airport due to thunderstorms".
'Safety is priority'
"Whilst this is outside of our control, we would like to apologise for any inconvenience caused as a result of the weather," he added.
"The safety of its passengers and crew is the airline's highest priority."
The airline added that: "Unfortunately, due to very high demand for accommodation in London Gatwick and flights to Belfast, we were unable to arrange alternative plans for all passengers and some of them were invited to make their own arrangements and get a refund.
"Our staff did everything they could to make their wait in the terminal building as comfortable as possible."
Gatwick Airport's spokeswoman said a total of four Easyjet flights to Belfast were cancelled on Friday as well as four Ryanair flights to Dublin, but she said not all cancellations were due to the weather.
Ryanair is facing industrial action by pilots in Ireland, Germany, Sweden, Belgium and the Netherlands and crews in those five countries staged a 24-hour strike on Friday.