Volker: In The Wind Gambit, all players have the same aggressive ability and the same passive ability for airships, so it's not possible for one player to have Toll and the other Blitzkrieg.
I'm thinking you may have played with the very advanced variant, which isn't recommended (I'm not even sure all airship interactions work under that variant, as the final design of the game wasn't focused on people using that variant), but I'll answer based on that just in case.
1. Yes, a Blitzkrieg airship can't enter a Toll airship's territory.
2. Airships are units.
That's my answer, but, again, I wouldn't recommend playing this way. Just use universal airship abilities like the rules say to do.