It is just nothing? I think you're bluffing. Now if you still think that you can convince us that waterspout is one of the fastest mobility technique of all the other elements, provide us this visual (video footage) evidence:
Have 4 different benders that is a waterbending, airbender, firebender, earthbender line up, in one block space apart from each other (to leave it fair, an exception goes for an earthbender to be 2 blocks away from the bender(s)). Cover the area with fence (while the benders are in that area). While all of the benders are allied at the start line, tell all of them to go rushing towards the finish line after the countdown, using only their respective travelling ability (AirBlast/AirScooter, Firejet, EarthSmash (for it to function proparly, the user will have to have 3x3 width racing space as an exception), WaterSpout). Make sure all of the conditions are met for each bender to succesfully performer this ability (a waterbender has his bendable source ready and selected, earthbender with their own elemental surface, ignitable ground for fireB. ect.). All benders begin the race without charging (those that need to) their ability before the race. All of them must go in a straight line, all of them in a same direction.
I guarantee, that a waterbender wouldn't outrun an airbender by any chance in this present condition after the outcome of this race.