Fighters are great for defence, that’s no lie. You want them, you need them, your allies can used them to help you in a quick pinch.
But everyone forgets… Infantry are the BEST Defence. There is no unit is better.
For the price of a fighter… 1 Hit Point… 1 dice at 4…
3 infantry + save an IPC… 3 hit points, 3 dice at 2…
Multiple this so it’s equal.
3 fighters = 30 IPC’s Total defence value 12. Statistically 2 hits a turn, with 3 hitpoints.
10 Inf = 30 IPC’s Total Defence Value = 20 Statistically 3.2 hits a turn with 10 hitpoints.
A few fighters on top of a stack of infantry is a strong defense
a SUPER STACK of infantry, with no planes - per above, is an even STRONGER defence.
The DIFFERENCE however, is all in the attack. The mobility of the fighters, and their punch, is what gives them the edge. You build fighters to attack, NOT to defend - though they obviously get used for that. And of course, a good offensive leads to an easier defence - hence why you build however many fighters you NEED, as opposed to just a fighter a turn every turn.