These 2 games don not have much to do with each other, and Ultra Fighters is a misleading title as it is a Sci-Fi game not concerned with fighter aircraft as we know them. It zips along okay, and can get addictive with the laser battles and repair bases to visit as you go.
If-18 is more a simulation, based on a very popular naval fighter in the interceptor and attack role. All this roles and the necessary carrier take off and landings are there, and the cockpit is really very realistic. the down side is the scenery that looks too much like a map with bits stck on as features. The sea is texturally flat as a pancake, so the realism suffers. The other thing to beware with this is the need for a HIGH resolution screen and a joystick as it will not even load without them.
The strange thing on this cd is a demo, which for me makes the whole thing worthwile, even though there is no mention of it on the box! Thaat demo is WarBirds, a truly masterful WW2 combat simulator based on fighters AND bombers. There are 30 or so highly detailed warbirds, all of which can be flown from lavishly detailed cockpits, and in the bombers you can even jump to the gun or bomb aiming positions and carry on combat there, before jumping back to fly the plane. All this happens in a landscape with nice details and loads of bases to either bomb, shoot at or land on. This is a basically online game, but the demo has enough planes to shoot at, and the Junkers 88 needs to be seen to be believed in what IT does! (I rated this package higher because of this demo!)