An (English) acquaintance of mine pronounces the word Aryan as
/ˈɛːrɪən/ (~Aerian). I have only ever heard it pronounced
/ˈɑːryən/ (~Aaryun). I have it on good authority that the word comes from Sanskrit's
ārya which is pronounced
/ˈɑːryə/ just as I expected.
The ODO cites 'Aerian' as the correct (as these things go) British pronunciation while accepting both to be acceptable in American English. Webster is another dictionary that accepts either variant. MacMillan, just to be difficult, only accepts 'Aerian' as the correct pronunciation for American English, and either for BE.
Now, in all my years of watching Nazi flicks, I don't believe that I've ever heard the word pronounced "Aerian"; I'm pretty certain that I would have noted the difference if I had. Is it a recent change? Or is it a regional peculiarity? How do the Germans pronounce it?
Also, how would the word indo-aryan be pronounced?