Vince Reffet initially thought the stunt would be relatively easy. He soon learned that base jumping from a 13,000-foot mountain peak, gliding and hitting a target little bigger than a body is the opposite of easy. After two months of training, however, that's exactly what Reffet and fellow wingsuit jumper Fred Fugen pulled off over the Bernese Alps in western Switzerland. A video by sponsor Red Bull shows the French duo known as the Soul Flyers leaping from Jungfrau Mountain and hitting speeds of 85mph, before hurtling through the open door of a Pilatus Porter aircraft flying at roughly 10,000 feet. The feat—inspired by French base jumper Patrick de Gayardon, who jumped and returned to a plane while wearing a wingsuit in 1997, per Red Bull—has been viewed more than 1.7 million times in two days.
Yet the two-minute video doesn't give any indication of the amount of practice the accomplishment required. "When we started to train, we thought it would be easier to be honest," Reffet tells Red Bull. "Then we realized that it was quite a technical and mental challenge. We had to be focused … It takes all your energy." The pair actually made 100 attempts, at least 20 of which were successful, before the main event, in which they used "a push-to-talk system" to communicate with each other and the plane's pilot, Philippe Bouvier, reports the Telegraph. Together, they "redefined the idea of catching a flight," per CBS News. "You're falling down and all of a sudden there’s no air anymore. The feeling is quite strange," says Reffet. "When you're in the plane and you see your friend flying closer and closer, it's incredible." (A legendary base jumper recently died.)