Lindbergh becomes a leading figure in the America First Committee, an organization that opposes U.S. intervention in World War II. He delivers speeches and writes articles arguing against American involvement.

In a speech in Des Moines, Iowa, Lindbergh accuses British, Jewish, and Roosevelt administrations of pressuring the U.S. into war. The speech is widely condemned as antisemitic.

Following the attack on Pearl Harbor, Lindbergh resigns from the America First Committee and offers his services to the U.S. military.

Despite his initial rejection from active duty due to his controversial pre-war views, Lindbergh works as a civilian consultant for several aircraft companies, testing new aircraft and developing techniques to improve pilot performance.

Lindbergh travels to the Pacific theater as a civilian consultant and flies approximately 50 combat missions with the U.S. Marine Corps and the U.S. Army Air Forces. He shares his expertise in fuel conservation and aircraft performance, significantly contributing to the war effort.