In Biggles in the Orient, Jangpur was the Indian terminal of the air supply route between India and China, with Chungking, being the terminal at the other end. Jangpur station was under the command of Squadron Leader Frayle and operated Wellingtons charged with ferrying urgently needed medical and other supplies to China.
Jangpur is a fictional aerodrome and Johns did not provide much detail about its location besides mentioning that it was about 100 miles from Calcutta.