The first trancontinental routes crossed via Rock Springs (6388 ft) and Rawlins (6834 ft). It's not immediately clear to me which planes they used, but that's o

The first trancontinental routes crossed via Rock Springs (6388 ft) and Rawlins (6834 ft). It's not immediately clear to me which planes they used, but that's over the Curtiss JN-4B service ceiling. The route was originally surveyed in 1920 by 3 cutting-edge Junkers-Larsen JL-6s, an American-built F13 (only 8 JL-6s were ever made!). Bert Acosta flew one of them. Map of the 1924 route: https://en.wikipedia.org/wiki/United_States_airmail_service#/media/File%3ATranscontinental_Air_Mail_Map_1924.jpg https://en.wikipedia.org/wiki/United_States_airmail_service#...