Slitherine

What does this do? Does it mean the unit can't fire back when being attacked from the air and, if so, why not make it 0? Does it mean the unit is actually more vulnerable from the air?

e.g. Pz IVH

Negative means it can defend against air attack but not initiate the attack. A zero would mean it can’t attack or defend against air attacks.

A tank can't initiate an air attack, though. All the examples of -1 air attack I saw in the pzeqp were tanks (there may be others, too).

I think I see what it does:
An attack against a Pz IVH, which has an Air Attack of -1 in pzeqp will show as a [1] in the unit stats - it will also give the unit a 1 Air Attack when responding to an air attack.
An attack against a Pz IVG which has an Air Attack of 0, will show as 0 in the unit stats and will not fire back when attacked from the air.

That's probably what you are saying Xerkis.
Cheers

Yeah, that’s exactly what I did say… well, in my head I said that.

BTW, any negative value works this way, not just -1.