Oddly, VTOL strafing is both a thing, and has better rule support then VTOL bombing. Problem is that VTOL's don't have a Bomb special ability in the MUL. It should be there, but no one thought about it when making up the lists. In general, VTOL's 5 to 29 tons have BOMB 1, 30 to 54 ton VTOL's have BOMB 2, 55 to 60 tons have BOMB 3. Super heavy weight classes were included because there are a few stock super heavy VTOLs. And if I were to simplify to Alpha strike levels. Combat Vehicle VTOL's have a bomb rating equal to their size. Slightly inaccurate, but details.
And yes, If a VTOL strafes or Bombs, any units in its attack's AOE fire back at it as though it were an aerospace fighter using its elevation as the range. (Course the VTOL also uses its elevation as it's range to target. Not certain if the strafing and bombing modifiers would be added to the range when figuring out the attacker's to hit number. Its less then clear, but probably.) Of course a unit that is just outside the attack area gets to ignore the elevation and just use the range to the VTOL's location at the end of its movement.
