The steering for a hovercraft is done through air deflectors placed behind the thrust duct. For these I just used the circle I had already cut out for the duct itself. I cut one of them in half and screwed a 1x2 on the rounded edge of each half. L-brackets were attached to the duct hold them on and allow them to turn. Then rope was attached to the deflectors and run through eye-bolts. The rope was criss-crossed under the duct so that moving the control stick left would turn the hovercraft left and right turns right. The control stick was just a piece of PVC pipe with a hole drilled through the bottom so that it could pivot.
The Thrust engine is controlled by a lawnmower throttle cable and the lift engine was locked into full throttle. I could have mounted the bike brake on the control stick but it would have been just one more thing to worry about so I just left it wide open.