Flying units

[Elrond]

Flying unit: Cavalry units with this special training ride griffons, hippogrifs, pegasi or other similar flying creatures, are equipped with light armor and fight with missile weapons, lances or medium martial weapons. Usually they exploit their tactical superiority by avoiding to engage non flying units and firing at the enemy from above.
Flying units identify hostile units in adjacent provinces (refer to the section on Strategic Movement for details) and, when attacking while flying, ignore any defensive bonus their target would normally receive from fortification or defensive terrain. They can’t fly in inclement or worse weather conditions or with limited visibility. Unit modifier: Melee -2, missile +2 while flying, movement +1 while flying, +5 GB muster cost. Special: While flying, the unit may enter an area occupied by a non flying friendly unit and can be engaged only by other flying units. Flying units can engage naval units if the battle takes place close to dry land (“shallow water” terrain) but can’t take off from naval units. Enemy units get +2 to their missile attacks against a flying unit. This special training is available only to cavalry units with light or no armor.

What do you think? Someone already created this kind of special training?