I've stumbled upon SR692 and his large collection of retro Swissair poster designs today. I'm not going to lie but their are some seriously good designs up in this collection. Most of these poster designs came from the 30's to the 80's, which are archived on the site.
What I like about this collection is the simplicity of each design. They utilize the generic airplane icon, a headline and the Swissair logo making for a minimally designed style. You can't go wrong with that. If you want to know more on the Swiss Airlines logo. I know that Wanken did a whole post on Swissair: Behind the Logos interesting read. You can find it on ISO50.