British Airways cancelled dozens of flights in and out of Heathrow Airport on Thursday evening because of a "technical issue", leaving thousands of passengers grounded.
Just before 9pm, the London airport's live departures and arrivals site showed 79 services had been axed.
This was despite the airline saying the problems had been resolved as they tried to get schedules back to normal.
In an earlier statement, it said: "While the majority of our flights have continued to operate today, we have had to cancel a number of Heathrow flights due to a technical issue.
"Affected customers have been contacted and offered options, including a refund or rebooking to an alternative flight with us or another carrier. We are extremely sorry to our customers for the inconvenience caused."
It's understood the company is trying to rebook customers on to alternative services where possible.
Sorina Anastasiu - a 33-year-old recruiter living in London - was due to get married in her native Romania in June, but she won't make it.
The law there requires couples to have their marriage rubber stamped 14 days before the wedding, so she was flying home to complete the forms.
She told Sky News: "You have to complete these forms 14 days before and I definitely can't do that now. So I've missed my wedding, basically. I had a bit of a breakdown about it earlier."
"It's been a really, really tough day. I've been here since three o'clock so it's been five hours now. I was supposed to fly to Romania because I'm getting married and needed to get paperwork done.
"Our appointment was tomorrow. Now, I can't get a flight until Saturday. The worst thing is that I've already checked in and they asked me to check my hand luggage, which has my ceremony dress inside it."
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She added: "Nobody can get their checked luggage back and there's nobody to help. There's just one landline phone in arrivals marked 'luggage enquiries' and that's the only way of contacting the baggage crew.
"All I have on me is my phone and my wallet. It's insanely frustrating.
"It's very poorly managed. I mean, my situation isn't life or death, but there are elderly people here, people who hardly speak English…There are people here who've got their medication in their bags and they can't access them.
"The staff are saying they'll reimburse us for hotels, but people have nothing on them - no clothes, nothing, so they don't want to leave. It's heartbreaking to see these people struggling in the airport with nobody to help them."