The flight to Ibiza was diverted to Toulouse for the man to get medical assistance, but he died in hospital in France.
The man, who has not yet been named, was flying from Manchester to the Spanish island of Ibiza when the plane had to be diverted to France because of the medical emergency.
He was taken to hospital by ambulance when the plane landed but did not survive.
A spokesman for Jet2, the airline he was flying with, confirmed the death on Saturday evening.
A Foreign Office spokesman said: "We are in contact with the French authorities following the death of a British man in Toulouse and are supporting his family at this difficult time."