There is a certain style that companies in the mid-20th century have. The vintage or retro look is pretty recognizable as compared to the modern-looking designs we have today.
Reagan Ray has collected an abundant list of classic airline logos from defunct airlines. And he has even gone further by looking at regional versions of different brands of airlines.
-via Kottke
(Image credit: Adam Moreira/Wikimedia Commons; CC by SA 4.0)