Captain W E Johns had written and published no fewer than eleven (prose) books about Flight Officer Joan Worralson of the Women’s Auxiliary Air Force, starting with Worrals of the WAAF in 1941, previously serialised in Girl’s Own magazine. Like her more famous male predecessor, Biggles, Worrals was a pilot known by an abbreviation of her surname, had a sidekick nicknamed after her physical appearance (“Frecks”, rather than “Ginger”), and showed an alarming propensity to stumble on spy rings while on routine missions. There was no romance, Worrals’s family never showed up, and she acted for King and country rather than personal interest.She's plucky, intelligent, independent and in charge of her own plane - what's not to like?
The author of the Worrals books, W. E. Johns, also wrote the Biggles books, of course, and several science fiction novels. His politics were clearly different from other children's writers of the era, as according to Wikipedia:
Unique among children’s writers of the time, from 1935 Johns employed a working-class character as an equal member of the Biggles team - "Ginger" Habblethwaite, later Hebblethwaite, the son of a Northumberland miner (we never learn his real Christian name, and he proclaims himself a Yorkshireman once or twice).
Other less-famous characters created by W. E. Johns include commando Captain Lorrington "Gimlet" King; aviatrix Joan "Worrals" Worralson (essentially a female Biggles, created at the request of the Air Ministry to inspire more young women to join the Women's Auxiliary Air Force); and pioneering astronaut (ex-RAF, naturally) Group Captain Timothy "Tiger" Clinton, who first rocketed into space in 1954.