Just ran North Africa again, only thing I'm unsure of now is a few of the air rules around interaction. Concentrating on the situations that can occur in this scenario only I believe the following can occur:
Only attacker can announce, cannot be intercepted, only attacker can reinforce in rounds after first.
Attacker announces, defender cannot intercept, only counter-support. No air combat, just add AFs to odds.
Attacker however can intercept defensive ground support, this leads to air combat, if the attackers withdraws any surviving defenders support the ground attack provided they didn't about in the last round of combat.
I'm working on the abbreviated SOP for the scenario here, but it basically looks like the attacker gets a *lot* more in the way of options compared to the defender.