Plenty of air, just not so good design, the bag was filling with water, I do have some ideas to improve it though.
Was a bit of a learning curve for control too, they don't turn too well at low throttle.
The rudder works from prop airflow, not the same as an airplane, so it will only turn with enough throttle input.
Here's a vid of it working, it's a bit long but you will see we get there in the end.
I used a plastic rubbish sack for the skirt which does not last long.
I just tried some heavier plastic but it does not work as well, need something somewhere in between.
I have the lift motor on a dial and the thrust motor on the throttle, both are shut down by the throttle hold switch
I set the dial to where it needs to be and leave it there and switch it on and off with throttle hold.
I have some pics somewhere, I will see if I can find them and add them to this post.
RC Hovercraft Maiden - YouTube