To do this, you must play as a Rebel Vanguard and set your three mines anywhere on the snowspeeder, preferably in front and the sides. After you take off, fly toward the AT-AT, AT-ST, or even turrets and units. As you got near, it is recommended that you slow down and as you head toward your intended target. Upon getting the unit in the mine detection radius, prepare to pull up quickly. And when the mine explodes, pull up quickly. If executed correctly, you can escape death yourself. This is probably the best and one of the fastest ways to kill an AT-AT. It could be your personal goal to aim for the neck, but be careful.