Radar Girls by Sara Ackerman

Daisy Wilder prefers the company of horses to people, bare feet and salt water to high heels and society parties. Then, in the dizzying aftermath of the attack on Pearl Harbor, Daisy enlists in a top secret program, replacing male soldiers in a war zone for the first time.

Under fear of imminent invasion, the WARDs guide pilots into blacked-out airstrips and track unidentified planes across Pacific skies. But not everyone thinks the women are up to the job, and the new recruits must rise above their differences and work side by side despite the resistance and heartache they meet along the way.