These were originally covered in a blog post, but the best place for these rules is right here in the rules section of the main site. These are a simple set of modifications to the basic Wings of War rules in order to use them with miniatures on a hex terrain.
Movement is done using new hex based maneuver cards. Currently, hex based cards are available for A, B, C and D maneuver decks. You can download them as a zip file containing these four maneuver decks: wow_hex.zip (2.5 MB zip file).
Planes are always oriented towards hex sides, not vertices.
Short range is 4 hexes, long range is 8 hexes.
The firing arc is found by drawing two lines from the center of the hex out through the vertices left and right of the hex side towards which the plane is facing. Hexes bisected by this line count as part of the firing arc.
The firing arc for rear gunners is the same from the rear of the hex, but excluding the hexes directly behind the plane.
The image below illustrates these firing arcs and ranges. The airplane is situated in the hex with the arrow, facing the hex side the arrow is pointing to. Darker hexes are within arc and in close range, light gray hexes are within arc and in long range. All other hexes are out of arc. The rear arc is only applicable for airplanes with an observer/rear gunner.