Ms Guan had no idea she was pregnant, with the couple saying a pregnancy test had previously come back negative.
A doctor they visited weeks before the flight also failed to spot the pregnancy.
When Ms Guan went into labour aboard the flight, crew members sought help from passengers.
Luckily for the couple, three doctors were on board the flight to assist them.
Flight staff upgraded them to first class for the birth.
The couple's daughter, Chloe, was born somewhere over the Pacific Ocean.
On arrival in Japan, the new family was escorted to a Tokyo hospital.
The Mother's Day birth was celebrated by Air Canada on Twitter.
