The seven-year-old French bulldog named Simba was taking its first flight when the pilot noticed the problem just as the plane was about to head over the Atlantic Ocean, where temperatures plummet.
With the dog's well-being in peril the pilot decided to land the plane in Frankfurt, Germany.
The dog's owner was more than grateful.
"It's my dog, it's like my child. It's everything to me," he said after they were reunited at Pearson Airport.
Aviation expert Phyl Durby said the pilot made the right call, despite tacking on about $10,000 in fuel costs and delaying the flight by 75 minutes.