(For the controls, a joystick or controller is necessary because it is not possible to fly with mouse and/or keyboard as the controls, even with the sensitivity low, handles horribly on keyboard.)
Wings of Prey is more of a pseudo-flight sim as it’s an arcade flight game that is trying to be IL-2 1946 (it even steals the name for the Xbox version! ;) ). It has all the bells and whistles of a sim but it doesn’t actually have the flight models that a sim should have. If you want to play it as an arcade flight war game, it’s all well and good, but it’s not actually a sim of the planes used. In general, the plane’s characteristics and controls are not accurate as a sim should be in terms of flight models.
When playing sim difficulty you can run your plane at full power and your engine will never overheat. Or, even better, you can play campaign on sim difficulty and have limited ammo and fuel and run out of both without having completed any objectives so the missions are not complete able with sim difficulty because they are not designed to be played as a sim. (Because there is no return line, as there is in Ace Combat, or a base to return to, as in an actual sim, once you’re out, you are out.) And you’re left there unable to complete the mission unless you bale out to get a new reloaded plane. Yes, baling out is the only way to reload your ammo.
In another way that this is not a sim, as is mentioned by other reviews, the AI does not use the same flight models that the player uses. Regularly you will see bombers out-flying single-seat fighters, which is ridiculous because you can’t use real tactics against bombers to shoot them down. Not to mention, the bombers’ gunners are extremely accurate. Also, in dogfights you’ll notice that in both arcade and sim difficulty that the AI will never stall or run out of speed as they’re not bound to the same physics as the player, which is frustrating in either difficulty. Due to this, the AI will zip past you are stalling out.