oh cool, how wil you steer it? if you havn't solved this yet, you might want to try using flaps, or even installing a few electric motors to seperate fans. OR if you really wanted you could use 2 transmission assemblies attached to a differential so 2 drivelines powered 2 fans, so you can engage and disengage power to the individual fans, do you get where i am going with this. Also if you do this you might want to use a diff, spool for equal power.
Oh and for extra power you should put the hovercrafts exaust out the rear, by the fans.