EasyJet passengers were left "vomiting and passing out" after being stranded in Italy because of new EU border rules.
About 100 people were marooned in Linate Airport in Milan while waiting to board a flight to Manchester.
Facing queues of up to three hours, passengers felt ill as a result of the heat and were unsure how to get home.
EasyJet said it was doing its best to aid passengers - but admitted the situation was "out of control".
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One passenger travelling with her boyfriend said it cost her mother £520 to book new flights to London Gatwick rather than Manchester.
Kiera, 17, from Oldham, told the BBC she had was offered just £12.25 by Easyjet in compensation for her missed flight.
She said: "We got here at 7.30am for our flight at 11am so were super early.
"We got to border control and it was a massive queue of people. I wasn't feeling great anyway because I think I'd got food poisoning.
Just 30 easyJet customers were able to board their flight to Manchester after new EES rules were implemented
"At about 10.50am they brought some water over for people, and when we got to the front of the queue someone asked us if we were going to Manchester, and told us our flight had just gone."
She estimated that just 30 people were able to board the plane before it took off.
Kiera said she will be stuck in the airport until her flight to London tomorrow.
EasyJet blamed the deays on the implementation of the new European Entry/Exit system (EES) which it said was "unacceptable".
The system was meant to be implemented in October last year - but became fully operational on April 10.
EES requires the registration of biometric information, including fingerprints and a photograph taken on the first entry to the bloc, with the data held in the system for three years.
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The new EU Entry/Exit system - intended to be rolled out in October - was finally implemented on April 10
|GETTY
Adam Lomas, 33, an accountant from Wakefield, was touring Milan with his wife Katy, 31, and their four-month-old daughter.
He said he had attempted to contact easyJet, but "just got chatbots".
After eventually making it through to a human, he said there were audio issues and "after five or 10 minutes they hung up".
Mr Lomas said he was planning to find a hotel and then book a flight to London.
The up-to-three hour delays occurred at Milan's Linate Airport
|GETTY
"We are just walking to a nearby hotel. Some passengers have driven to Pisa to fly," he said.
He added: "We thought it best to limit our movements because of the baby and so we waited around the airport for a long time before it became apparent that nothing was really happening.
"The airport and easyJet have spent hours arguing with each other about who is to blame."
A spokesman for easyJet said: "We are aware that some passengers departing from Milan Linate today experienced longer than usual waiting times at passport control and we advised customers due to fly to allow additional time to make their way through the airport.
"We have been doing all possible to minimise the impact of the airport queues, holding flights to allow customers extra time and providing free flight transfers for any customers who may have missed their flight including EJU5420 to Manchester.
"We continue to urge border authorities to ensure they make full and effective use of the permitted flexibilities for as long as needed while European Entry/Exit System is implemented, to avoid these unacceptable border delays for our customers.
"While this is outside of our control, we are sorry for any inconvenience caused."