@Olmate
Welcome to the forum.
The rulebook should be clarification enough (1940 Pac.2nd ed., page 15):
“A quick reaction team of no more than 3 defending fighters and/or tactical bombers (strategic bombers can’t scramble) located on each island or coastal territory that has an operative air base can be scrambled to defend against attacks in the sea zones adjacent to those territories.”
As you correctly stated this wording clearly doesn’t include fighters located on carriers in seazones.
Why should something not being part of the rules be explicitly stated in the rulebook? Or in any FAQ/Errata when the wording of the rule is clear enough? There are hundreds of House Rules that might fill what people are missing being included in game rules / rulebooks.
There of course exist player created variants of Global1940 that have scrambling from carriers included.