They took off in wooden crates loaded with gasoline. They flew over mountains and seas without radar or radios. When they came down, their landings might be their last.

For pilots of the 1920s and ’30s, the challenges were enormous. Multiply that exponentially for women. In “Fly Girls: How Five Daring Women Defied All Odds and Made Aviation History,” author Keith O’Brien recounts the early years of aviation through a generation of female pilots who carved out a place for themselves and their sisterhood.

O’Brien begins his story in the 1920s, when planes were “airships” and all aircraft were experimental. Charles Lindbergh inflamed the country’s imagination in 1927 by completing the first solo transatlantic flight.

It was understandable that his feat would draw more men to test their limits. But why were women coming forward, too? Should women even be allowed to fly?

The women who stepped up to answer those questions included a New York socialite, an Oakland saleswoman, a Florida dentist’s secretary and a Boston social worker who would become world-famous.

“Why do you want to fly the Atlantic?” Amelia Earhart was asked before her first ocean crossing in 1928. “Earhart thought for a minute and smiled. ‘Why does a man ride a horse?’” she replied.

Female pilots may have gotten their first chances because of their gender, but they wanted to show what they could do despite it. They were greeted with smirks and shrugs.

The press dubbed the first women’s national air race “The Powder Puff Derby.”

The inevitable crashes brought more indignity. No matter that men crashed, too. Marvel Crosson’s wreck prompted oilman Erle Halliburton to announce, “Women are lacking in certain qualities that men possess.”

Yet they persisted. The story builds to a thrilling climax with the 1936 Bendix race, a cross-country contest that featured Earhart and the men heavily favored to beat them. O’Brien’s rich details put the reader in the cockpit.