airmail, an unusual kind of mail, had an even more rare version, the ClipperGram

https://www.facebook.com/photo/?fbid=26743404241962476&set=gm.27281379991464035&idorvanity=164403560255045

Stamps issued by the United States and Philippine Islands for Air Mail carried on the first flights in each direction of PAA's Transpacific "China Clipper" service between San Francisco, California, and Manila, Philippines

a roundtrip flight between California and Manila took fifteen days in 1935. It took eight days to reach Manila from Alameda, with stops in Honolulu, Midway Atoll, Wake Island, and Guam.

https://www.facebook.com/photo/?fbid=1178179699041921&set=during-world-war-ii-lockheed-constellations-were-designated-for-use-by-the-milit

Flying Boat, a documentary about the golden age of the flying boat, and the people who keep the surviving examples in the air today

Realizing that major cities had harbors, Juan Trippe, the innovative chairman of Pan American Airways, surmised that long distance air travel would require flying boats. Beginning in 1931, Trippe commissioned a fleet of aircraft he called Clippers, named for the swift, topsail schooners that plied merchant trade during the 19th century.

https://silodrome.com/flying-boat-documentary-dirk-braun/

1935 - Martin 130 Clipper and Desoto Airflow

https://www.facebook.com/photo/?fbid=714708006689249&set=a.197924875034234

I just learned there is a Facebook page for planes with cars photos

https://www.facebook.com/photo/?fbid=3253957901504452&set=gm.3103096356570711

https://www.facebook.com/groups/568127127055465/posts/1201235473744624

for more on the Junkers see https://justacarguy.blogspot.com/2020/04/hayao-miyazaki-and-studio-ghibli-have.html

and https://justacarguy.blogspot.com/2016/02/junkers-g38-amazing-aircraft-with.html for detailed images

the Pan Am Sikorsky S-42 Clipper Ship at Pan American Dinner Key Airport in 1938.

French photocolorist Benoit Vienne has colored Pan American classic DC-4, DC-6, DC-7, and DC-7C propliners

https://www.airlineratings.com/news/stunning-new-colorized-images-douglas-propliners/

colorized photos of Pan Am Clippers

this above photo makes great wallpaper

https://www.flickr.com/photos/14024074@N05/with/50005205468/

how to test airplanes when you don't have access to a wind tunnel I guess

https://www.jalopyjournal.com/forum/threads/vintage-shots-from-days-gone-by.428585/page-6630

“Travel in Vogue” by Gary Whinn features a Pan-Am Clipper plane and a 1936 Cord 810

http://therebelgentleman.tumblr.com/

imagine what an incredible thrill it must have been to get a ride in a clipper

https://www.flickr.com/photos/michaelryerson/15081747091/

one heck of a good photo of a Pan Am clipper ship

From Shorpy.com 

Cool stuff found on Greyhandgang.tumblr.com

All from http://www.greyhandgang.com/ which is a collection of cool photography mainly focused on pop culture and 70's era design styles

Clippers, a flying and a floating

found on http://www.mission4today.com/index.php?name=ForumsPro&file=viewtopic&t=14428&finish=15&start=0

Terrific variety of aircraft posters at Moment d'Inspiration Blogspot

Just a couple I liked the most from a big gallery at http://momentdinspiration.blogspot.com.au/2012/04/vielles-affiches-daeroplanes-ii.html

above from a seperate post at http://momentdinspiration.blogspot.com.au/2011/06/airplanes-cutaways-iii.html