People on Flight AC33 said the plane suddenly dropped Thursday afternoon causing some to be thrown upwards and hit the ceiling.
The turbulence happened at around 10,973 metres of altitude and about 966 kilometres southwest of Honolulu, according to the U.S. Federal Aviation Authority.
The plane, which had been travelling from Vancouver to Sydney, Australia, turned back to make an emergency landing at the Honolulu airport.
Around three dozen people were injured, with 30 taken to hospital.
A spokesperson from Air Canada said all 37 people who were injured or assessed had been released from hospital.
WATCH: ‘Everyone just went flying’ — Passengers recount turbulence on Vancouver-Australia Air Canada flight
Flight AC33 was expected to resume its flight path to Australia on Friday at 12 p.m. Hawaii time with another aircraft and crew.
Passengers described the moment of turbulence as chaotic and terrifying.
Michael Bailey said there were only a few seconds of warning before the plane dropped.
“We just hit turbulence, it was pretty quick, and a lot of people hit the ceiling. A lot of screaming. The seat in front of me, the girl hit the plastic overhead and actually snapped it, broke it, and the oxygen masks came down and a lot of panic,” he said.
“It was probably one of the scariest experiences of our lives, I can say pretty confidently,” guitarist Tim Tricky of Australian band Hurricane Fall told Global News.
“It was a massive drop, and the whiplash we felt from the back of the plane [where we were], it kind of went up first and then just smacked straight down.
Both Transport Canada and the FAA continue to investigate the incident.
In a statement, Transport Canada said it “takes all reports of turbulence seriously” and that when severe turbulence is reported, it follows up with airlines to ensure proper procedures were followed.
WATCH: What causes airplane turbulence?
*With files from Simon Little and Global News