Fog!
Written by
W. E. Johns
Copyright 1932
15th of 17 stories in . It was republished as Lost in the Sky in The Modern Boy #271, Apr 15, 1933.
Heading back to the War from his leave, Biggles is plagued by fog and has to make an emergency landing in what turns out to be a camouflaged German petro supply dump. He also comes across a British spy.