Depending on details of the flight magic, weather magic might become critically important.Counterfactual theorizing time! Say one side of a conflict Figured out a magical way to get big ships airborne, but did not develop explosives. What other tactical and strategic advantages would they be able to implement?
I have some ideas, but I'd like some fresh perspectives and possibly new thoughts. Thanks!
If countermagic is straightforward, this might limit uses to logistics and communication in safe territories.
In the early days the simple terror effect might be substantial.
If there is already an aerial combat arm e.g. winged mounts, it might only add a troop type like a move fortress to that battle domain, changing aerial tactics, but less influence on logistics.
Many applications of flight are also covered by teleportation and a scrying: so if these magic are already powerful, strategic impact might be limited.
Rapid long distance communication by chains of zeppelins dangling strings of coloured flags.
Safe battle command station. But some kind of messaging system is needed to relay orders to the troops.