Ambulances meet the plane at Tokyo's Narita airport
Forty-seven people were injured when an airliner was hit by severe turbulence as it neared the end of a flight from Manila to Tokyo.
Terrified passengers told how those without seatbelts fastened shot up and hit the ceiling of the plane.
At least six passengers on the Northwest Airline plane were seriously injured, officials say.
Turbulence struck while the plane was circling off the coast of Chiba, east of Tokyo, an airline spokesman said.
Ambulances met the plane at Narita International Airport, near Tokyo, and ferried the injured to hospital.
The Boeing 747-400 plane had been carrying more than 400 passengers plus 14 crew when the incident happened on Friday.
The flight had been set to continue on to Los Angeles after a stopover.
"The 47 people were taken by ambulance to six hospitals," said Sayuri Naito, a spokeswoman at Narita municipal fire and disaster management headquarters said.
Six people were expected to require hospital treatment of up to three weeks, while the 41 others suffered lighter injuries, she told the AFP news agency.
"The plane started swaying left and right all of a sudden, then people flew up," a male passenger told the TV Asahi network.
"They bumped hard against the ceiling twice. It left at least three holes in the cabin ceiling as far as I could see," he said.
Northwest Airlines spokesman Masashi Takahashi said the turbulence happened 25-30 minutes before landing, when the seatbelt light was on.
"During the flight, we received a message from the pilot saying two or three people were injured. But [the pilot] probably assessed that an emergency landing was not necessary," he said.
"It is possible that the people injured did not have their seatbelts on, otherwise all of the 422 passengers would have been injured as well."
Japanese media quoted witnesses saying that those who had not fastened their seatbelts had been sent crashing into the ceiling as the plane shook violently.
"I was so scared, I thought I would die," an unnamed male passenger told Japan's TBS television network.
The flight had been due to continue on to the US
"The plane shook so much, and my whole body hovered up in the air. Inside the cabin, everybody was screaming loudly," he said.
Another passenger told the broadcaster: "The person in front of me flew up to the ceiling. The person behind me collapsed and looked unconscious."
Vincent Salazar, a 55-year-old American passenger, told the Kyodo news agency that he heard screams when the plane suddenly descended and then made an ascent about 30 minutes before landing.
"It really happened so fast and it was over," Mr Salazar said.
"We were flying and then the seatbelt sign came on and when we were trying to get back to the seats, the plane dropped and so some people went up and hit the [ceiling]."
"I actually was pretty calm because I've flown a lot, but the lady next to me was screaming... And unfortunately some people weren't in their seatbelts. They were just flying," he said.