Watch: Wingsuit flyers jump from top of mountain into plane mid-air

French wingsuit fliers Fred Fugen and Vince Reffet pulled off an incredible stunt over the Swiss Alps, leaping from the top of Jungfrau mountain and into a moving plane.

The duo, known as the Soul Flyers, spent months training for the stunt, completing more than 100 test flights.

"When we started to train, we thought it would be easier, to be honest. Then we realized that it was quite a technical and mental challenge. We had to be focused," Reffet told Ruben Curiel of RedBull.com. "During the first training session in Spain, Fred managed to fly into the plane, but I failed and hurt my ribs. One month later, we came back for another session. We felt better and it worked out. We managed to make it five times."