The trick with classic style sunglasses for cycling is to get them with comfort cables - the arms that wrap fully around your ear. They will not come off in even extreme weather conditions. For aviators, get oversize lenses and then you will be seeing through them even when looking up from deep in the drops. American Optical make the kind I'm talking about.

(but the best kind I own personally are 80s vintage Jubo skiing glasses sans leather bridge and side shields, purchased NOS in Switzerland 5 years ago. They had a whole rack of them, hauled out of an ski lodge shops' cellar. If I could go back in time....)