Pope Leo spent half an hour in the cockpit of a plane on Monday, chatting with the pilots and speaking by radio to the crews of the Rafale fighter jets escorting his aircraft, Air France said.
The leader of the world's 1.4 billion Catholics is wrapping up his four-day visit to France with a trip to the northeastern city of Metz, near the German border.
On Monday morning, the 71-year-old pontiff and aviation enthusiast, spent around 30 minutes in the cockpit of the Air France aircraft that flew him from the southwestern city of Lourdes to Metz, the final leg of his apostolic journey.
"The Holy Father came into the cockpit for the entire Lourdes-Metz cruise phase," said Eric Marguerite, the flight's co-pilot.
"We had informal conversations with him. He is passionate about aviation, cars and mechanics in general," he added, after landing in Metz.
The flight, commanded by Captain Clemence Coussonneau, was escorted by two Rafale jets flying about 50 metres (yards) from the pope's plane.
"We handed the microphone to the Holy Father, who spoke to the Rafale pilots," said Marguerite.
"He offered his blessing to them and to all military personnel working to protect people and promote peace around the world."
The pope also took time to greet the cabin crew on board.
"After all the meticulous planning that went into this flight, receiving a blessing from the pope in person was a unique moment," flight attendants Landee Van Keeken told AFP.
Throughout his trip -- the first official papal visit to France in nearly two decades -- Leo appeared smiling and warm, readily engaging with crowds.
He blessed countless babies, celebrated a giant mass in Paris at the weekend and engaged with young people at the packed Stade de France stadium.