I decided to distinguish my clone version by using a d6 instead of a d10 and folding some locations that may or may not be present (rider, wings) into other locations. Some time ago, I suggested using approximate height off the ground for a six-foot tall human being of normal proportions as a way to randomly determine armor by the piece... and I could swear I also suggested that as a system to randomly determine injury locations after a fall, but I can't find that post. I adapted the same concept to hit location for flying creatures.
A hit to "forequarters/wings" or "hindquarters/rider" requires rolling again if both alternatives are reasonable: 50-50 chance of either. Attacks from the front are more likely to hit the head, unlikely to hit the tail, so add 1 to the d6 roll; they are also probably going to hit a rider rather than the hindquarters, in most cases. Attacks from behind are the inverse: subtract 1 from the d6 roll, and always treat "forequarters" as "wings" in most cases. Attacks from below can't hit rider or wings, attacks from above can't hit forequarters or hindquarters, if there are wings or a rider.
The height-based hit location chart is a necessary bonus, since it makes more sense when attacking characters using Fly or Levitation. As I said in a comment, I originally intended "arms/chest" to just be "arms", but decided to add "chest" based on apparent height in the diagram. This was probably a mistake, and I should either change "chest" to just "shoulders" or drop that part completely. "Feet" and "Legs" are different because of at least two situations:
- An unarmored character wearing thick boots, bitten by a snake or stung by a scorpion (for example,) should get at least AC 7 for an attack to the feet;
- Any character wearing magic boots struck by acid, fire, or similar attacks on a specific location needs to know whether the boots are struck and in danger of being destroyed.
- Reduced Speed: the flier is still in combat.
- Dive and Land: the flier can remain in combat, if able to attack from the ground, and may be able to rejoin combat in a couple rounds.
- Withdraw: the flier is out of combat entirely, unless a leader is able to take charge and urge them back into the fray.
- Crash: probably results in death, but in any case, definitely out of the combat.
d6 Result Head Wing Body
--------------- ---- ---- ----
Extremely High C W C
High W W W
High Average W D W
Low Average D 1/2 D
Low D 1/2 D
Extremely Low 1/2 1/2 1/2
The abbreviations should be obvious, based on the previous list. This pretty much covers aerial combat (except for bombing, which is trivial.)