Build a vehicle with 200 blocks or more and go over a set speed
For this you will want to make a vehicle out of all Heavy Body types until it won't let you add anything more (this will be the 200 max), then head to Nutty Acres. Use a flying vehicle to go straight up to the ceiling of the level, then make sure there are no clouds in your path and pause the game. Select "change vehicle" and select the Heavy vehicle you've made. You will now be falling to the ground in your heavy vehicle. Hold UP on the control stick to tilt your nose down for more speed. If you fill the speed guage all the way before you land the achievement will unlock.