There are three basic ways to do this. In coop, have your friend fly a helicopter, while you hold onto the side handle for ten seconds. By yourself, fly a helicopter straight up and jump out to fall for ten seconds. By yourself, use a hang glider and stay in the air for ten seconds.
Here is a video guide with English commentary!
Here is a playlist of guides for this game!
https://www.youtube.com/playlist?list=PL-HeW6XkKdUISTHMzTXDO...