Turtle Wax
I have tried everything that I could think of. (that was safe for the paint) Simple Green's Aircraft Cleaner, Aero Wash & Wax, every aircraft cleaner that Sporty's sells. Nothing I have used works as well as Turtle Wax in the spray bottle it takes the bugs and oil off and leaves a very smooth slick surface. Bugs don't stick as well and the aircraft never needs waxing. Its relatively cheap and can be bought at Walmart.