[HeWhoLurksLate]

Wanted to add that a bunch of planes from back then didn't have sealed, heated cockpits like we know today.

[TylerE]

The vast majority of military cockpits aren't pressurized even today.

[pathseeker]

Yes, they are (F-16 most commont)[1] (F-16 pressurized)[2]. It's just not enough to avoid needing additional air supply to prevent hypoxia.

1. https://en.wikipedia.org/wiki/List_of_active_United_States_A... 2. https://aviation.stackexchange.com/questions/73143/is-the-f-...