An Air Canada flight bound for Sydney was forced to divert to Honolulu after sudden turbulence injured 35 people.
Injuries were described as minor and it landed safely in Hawaii without incident.
The Boeing 777-200, carrying 269 passengers and 15 crew, hit clear air turbulence and plunged about 100 feet according to passengers.
"Five to 10 seconds and then bang, all of a sudden it dropped. It must have dropped like a 100 feet or something because people went up to the ceiling throughout the plane," Australian Michael Bailey told ABC Radio.
"It was pretty scary."
One passenger estimated about half were not wearing seatbelts at the time.
Turbulence incidents are the biggest cause of non-fatal mid-air injuries according to the US Federal Aviation Administration.
It costs US airlines an estimated $200 million annually, and scientists say climate change is causing more frequent occurrences.
