Simple. The airbase is located near the coastline, so planes can fly 0-50 miles or whatever out to sea to defend.
Planes in Berlin shouldn’t be able to defend Poland in the same manner, no.
Larry’s Alpha + includes a clarification that planes on a Jap airbase couldn’t defend against an amphibious assault (if no naval battle) on Korea. That’s because the Korean coastline is too far away from the Jap airbase for scrambling….
Lastly, remember A&A is an abstraction. Not all the rules have good reason.
In AA50 you can bombard France from the Mediterranean immediately after France is captured by an amphibious assault from Z7. Battleships that can launch salvos hundreds of miles with pinpoint accuracy?
Just roll with Larry’s rules and enjoy the game, man. Scrambling is for sea zones only. :lol: