BERLIN - Passengers of budget airline Ryanair have expressed anger over the way the company treated them after their plane was forced into an unscheduled landing in Germany that forced dozens to seek hospital treatment.

Thirty-three Ryanair passengers were treated in hospital, some bleeding from their ears, after their plane lost cabin pressure and made an emergency landing in Frankfurt on Friday, German police said.

In interviews with German and Irish media, passengers described moments of terror as their plane - flying from Dublin to Zadar, Croatia - descended suddenly, following what Ryanair said was a drop in cabin pressure.

Oxygen masks fell from the ceiling and passengers reported feeling intense pain in their ears until the plane levelled off and landed at Frankfurt-Hahn airport.