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, e.g. This is how I got it, I pushed the analog stick to the left at the last second, a mine was on the right, the achievement unlocked, this was on the Rogue's Landing course. It can take some practice but you will eventually do it. Hope this helps :)