History: First day of the U.S airmail service, May 15, 1918. [1050 x 832]

https://i.redd.it/7kjwxzsvmh851.jpg via /r/HistoryPorn https://www.reddit.com/r/HistoryPorn/comments/hk2kh1/first_day_of_the_us_airmail_service_may_15_1918/?utm_source=ifttt