Passengers on Flight AC088, which was diverted to Calgary on Wednesday afternoon, described what it was like on board the Boeing 777-300ER. The turbulence occurred well into the flight from Shanghai.
Twenty-one passengers were hospitalized, officials said.
None of the injuries -- possibly to the neck and back -- was life-threatening, said Stuart Brideaux, public education officer for the Calgary Zone EMS. Three children were transported.
"It's fortunate we don't have greater injuries," Brideaux told reporters.
Passenger Gord Murray told CNN newsgathering partner CBC News that "it could have been much worse."
"It was a little scary ... but all the crew were very professional. They handled themselves really well. Everyone stayed calm," he said.
Murray, who flies a lot for work, said, "It was the most turbulence I've ever felt." He related the story of the beverage can. "We dropped quite a bit."
The traveler said the crew had warned passengers they were in for some turbulence. "They were good at communicating." The initial plan, Murray said, was to land at Edmonton, also in Alberta.
The passengers did not know where the turbulence occurred and Air Canada did not provide details. Medical professionals who were on the flight helped the injured.
Passenger Linda He said a girl next to her was sleeping, apparently not wearing a lap belt. That passenger went flying into the air, He said.
Air Canada said eight passengers suffered non-life threatening injuries and 13 were hospitalized for observation. Some of those taken to hospitals were released later in the day.
An investigation was underway and teams were assisting passengers affected by the diverted flight, the airline said.
Yi Lee of Halifax said "all of a sudden it was really violent." The lap belts sign was on, but some people did not have them on or they had not been tightened, he said.
The plane was carrying 332 passengers and 19 crew members.
Klaus Goersch, Air Canada's chief operating officer, said: "Our focus today has been on those passengers who have been injured in this incident and those other passengers on the aircraft for whom this has been a very unsettling experience."