Donna Howl (43) flew out of City of Derry Airport on Saturday morning with her partner Eamon Doherty (49) and children Keela (13) and Lochlan (8).
Their return flight on Thursday has now been cancelled, while their car is still in City of Derry car park.
The sudden collapse of flybmi means an added cost of £310 for new flights, baggage costs and extended car hire.
“We just couldn’t believe it. If they knew this was going to happen, why did they put us on the flight out?” she asked.
“It’s an absolute joke, it’s ridiculous.”
The airline said rising fuel and carbon costs had contributed to the decision, and Brexit had “seriously affected” the airline’s prospects.
“I was shocked they blamed Brexit. It’s an easy excuse,” said Ms Howl.
“My son is autistic, so we had made arrangements for him at City of Derry Airport.
“So I had to spend all of Sunday making new arrangements, because he can get very frustrated and upset.
“We’re leaving at 3.30 am in the morning now, because the cost of the flights is cheaper.
“We were so stressed out and felt we couldn’t enjoy our holiday till we got it sorted, it’s been a nightmare.”
She added: “I also called the car park in Derry, they said we might have to pay another day and asked if there was any way I could come and get it.
“I actually had to say: ‘No, I’m in England and there’s no way I’m paying for another day’.”
Sally Lynch (44) from Derry had booked flights costing £250 for a family holiday to England with her husband Liam (48) and son Aidan (15).
“I got a text on Saturday night to say they’d all been cancelled,” said Sally.
“I’m so annoyed, because they must have had an inkling they were going to go into administration and they still let us book our flights.
“We paid by debit card, so we don’t know if we’ll get our money back or not.
“It’s very frustrating. You work hard and look forward to something like a holiday, especially as money doesn’t go as far these days.”
The family have held off from booking alternative flights.
“I don’t have the money unless we get a refund,” she said.
“We were going out to visit my family, but now I don’t know if we can.
“I looked at flights from Belfast and they are more expensive, as baggage isn’t included. I liked flybmi, I thought it was a very good service.“I prefer using the smaller airport anyway, as my son Aidan has ASD (autism spectrum disorder). Belfast International can be crazy and you had all the problems with security delays last year.
“I was just so relieved we were flying from Derry.
“They’ve blamed Brexit, but it hasn’t even happened yet. I don’t think they can use that as an excuse, it’s a bit ridiculous.
“I feel sorry for all the people who work there as well, who won’t have jobs.”
Civil engineer Danny McLaughlin (46) from Buncrana in Co Donegal had 14 flights booked through his job between City of Derry Airport and London Stansted.
He said the collapse of flybmi was his first experience of living in “Brexitland”.
“For me personally it’s the first thing really that’s affected me,” he said.
“And then (by March 29) we just don’t know what’s going to happen.
“If there’s going to be a no-deal, and it looks that way at the minute, this area here, we’re going to be hit the worst.”