Capt. W. E. Johns 
Worrals of the W.A.A.F. [EPUB ebook] 

Worrals and her friend Frecks are two capable and adventurous members of the W.A.A.F. An unexpected opportunity to ferry a plane begins a series of thrilling discoveries, and they find themselves on the trail of an enemy spy gang operating near their aerodrome. After capture, rescue, and exciting chases the spies are outwitted through the girls’ heroism and quick wits.

Authentic Air Force detail makes this a fascinating and unusual tale, and Worrals will become as popular and well-loved as her 'brother’ adventurer, Biggles—a character who is at once the envy and delight of boys of all ages.