More than 30 Ryanair passengers were hurt after one of its aircraft lost pressure in mid-air.
German police said 33 of 189 passengers were admitted to hospital, some bleeding from their ears, after a flight from Dublin to Zadar in Croatia had to make an emergency landing in Frankfurt Hahn airport on Saturday.
The aircraft reportedly descended 26,000ft in seven minutes.
It is standard procedure in the event of in-flight depressurisation to descend rapidly to an altitude at which passengers and crew can breathe unassisted.
The airline said oxygen masks were deployed and the crew carried out a “controlled descent”.
Passengers also criticised their treatment once they had landed, saying they had not been given enough food and drink and had been forced to sleep on a concrete basement floor or on camp beds.
Ryanair said: “The aircraft landed normally and customers disembarked, where a small number received medical attention as a precaution.
“Customers were provided with refreshment vouchers and hotel accommodation was authorised, however there was a shortage of available accommodation.”