Dozens of passengers were reportedly injured after a Ryanair flight lost cabin pressure, with some left "bleeding from their ears, mouth or nose".
The flight from Dublin to Croatia was forced to make an emergency landing in Frankfurt on Friday.
German police said 33 of the 189 passengers on board were taken to a nearby hospital after complaining of headaches, ear pain and nausea. All were able to leave by Saturday morning.
One passenger wrote on Facebook that the air went cold and oxygen masks dropped, saying the plane dropped "3,000 metres in less than one minute”.
Ryanair said that following an "inflight depressurisation" the crew deployed oxygen masks and "initiated a controlled descent" which was "in line with standard procedure".
Minerva Galvan Domenech, from Spain, told Spiegel Online that passengers, some of them bleeding from their ears, mouth or nose, had to wait 45 minutes before being allowed to leave the plane.
Sarah McGarry told The Irish Times that her eardrum burst during the descent but she did not go to hospital because she did not know if she would miss the next flight on to Croatia.
She told the paper: "We’re flying and next of all the oxygen mask comes down, we’re left in darkness for 15 minutes, there’s no reassurance just people shouting ‘emergency, emergency’.
“There was a newborn baby and children on the flight, people are screaming and we don’t know what’s going on for 15 minutes. Then finally we’re told that we’re going to Germany.”
Another unnamed passenger told the paper "it was really scary, there were three to four minutes (that felt like an hour) when the plane was falling fast and I thought we were done for”.
Some passengers complained about their treatment by the airline following the landing, with some having to spend the night at the airport.
Ryanair acknowledged that there was a shortage of accommodation for passengers who had to wait until Saturday morning for another flight. It said passengers had received refreshment vouchers.