Jacqueline Frater and her husband, Melvin, were flying back from Milan to East Midlands Airport in Derby, England, Wednesday aboard the Boeing 737-800 when they heard a bang, then felt a rush of cold air, Sky News reported.
Jacqueline Frater described passengers' reaction, the BBC said.
"You could see the whites of the eyes of the people next to you. People were panicking but they weren't screaming or shouting," she said. "You overheard the captain saying, 'Mayday, mayday!' and he was saying it rapidly as we were going down. I thought my number was up."
Her husband said he saw snow-covered mountains "approaching fast" outside the windows of flight FR 1703, which was carrying 134 passengers.
Passengers put on oxygen masks and "the plane began to make a rapid descent," Melvin Frater said.
After the plane leveled out, he said, the captain apologized over the speaker system.
The plane was diverted to Frankfurt, Germany, and passengers were transferred to another plane for the trip back to East Midlands Airport.
Ryanair said three people who had ear pains were released from the hospital.
The airline released a statement apologizing for the incident.