Your vehicle has to be in plane form to attempt this achievement, it can be done on any course that has allows you to fly. To perform a reckless boost, you simply have to avoid an object or obstacle that is in your way in the very last second by pushing the right analog stick, up, down, left or right depending on what way the object/obstacle has to be avoided. It's recommended you do this on Rogue's Landing, since it will be useful for completing the Time Trial on it