I didn't find L+R+U worked, but L+R+Z did.
The way your control instructions read it seems you intend for folk to hold L+R+U the hold time they are flying (except releasing L or R to turn), but that just had me spinning-- holding Up alone, and using L or R to turn as needed worked.
Sometimes when trying to get passengers onto the platform if I walked at the platform I was shoved backward; jumping on approach and to get up fixed this.
It would be nice if there were a way to tell the passengers get into the ship without having to walk past(and possibly pick up more that you can't stop), and to stay put (so they don't get fried on the landing pad if you accidentally pick up too many), but I assume that is intentional as part of the challenge?
Fun concept, needs some work on the controls and sound-- that ending is WAY too loud all of the sudden.