20 Hrs. 40 Min. recounts Amelia Earhart’s 1928 journey across the Atlantic aboard the Friendship, a Fokker aircraft piloted by Wilmer Stultz with Louis Gordon as mechanic. Earhart describes the preparations, departure from Newfoundland, difficult weather and eventual arrival in Wales. Her account incorporates entries from the flight log and records the practical conditions of long-distance aviation at a time when transatlantic flying remained hazardous and uncommon.

The book also ranges beyond the flight itself. Earhart recalls her early experiences, her introduction to flying and the development of her own aviation career. Later chapters consider the growth of commercial aviation, technical and organisational challenges facing the industry, and opportunities for women as pilots and aviation professionals. The result is both a personal record of a widely reported flight and a contemporary account of aviation during a period of rapid development.