The 109 cockpit is cramped to anyone except a child. I'm sure even the german pilots back then thought the same. To it's defence I'd like to believe that being rather squeezed in there made one feel more in symbiosis with the plane, like an extension of yourself. The feeling I got from watching that clip was very claustrophobic especially the lack of room for movement. I'm quite small by western standards (171 cm) but that cockpit would probably be small for me too. The 109 is one of my favourite WWII aircraft but that doesn't make it perfect
....that's also why I like it.