1927: Sven Hedins Zeppelins over China
The famous swedish Asia-explorer Sven Hedin was lobbying in the 1920s for an airship-route Berlin - Moscow - Beijing . The problem was expected hydrogen- and fuel-loss due to high mountain ridges and heavy winds - both were unknown entities at the time over China.
From: (https://epic.awi.de/id/eprint/48657/1/PF88-1_23-30.pdf)
With the financial backing of German officials and Junkers, Hedin could start in 1927 a huge scouting expedition with planes into Chinas Xinjiang province, accompanied by 8 Lufthansa pilots.
Here you fly a Junkers F-13 with extra tanks to reconnoitre the unmapped Urumqi corridor. The Jus service ceiling (16.500ft) just matches the peaks.
CHINA_Hedin.PLN (4.4 KB)
Needless to say that no airports did exist at the time 
:
In the end this Zeppelin-project never materialized - but with the upcoming Hindenburg add-on it might be a thrilling “what-if” for lighter-than-air enthusiasts (estimated was 80 hours in-flight, one way…):
LZ129 HINDENBURG for MSFS TEASER - INSIDE (youtube.com)