At the end of the Great War in 1919, William L. Mitchel —theoretician and father of military aviation in the United States— predicted that air passengers would be as common as train passengers and that distances between large cities would be calculated in business hours flight instead of kilometers. In 1936, John A. Wilson, Canada’s head of Civil Aviation, coined the term World’s Airways System, which he claimed would represent a revolution in transportation. Such predictions are the guiding threads of this book. This work shows how this field of aviation was born and developed in the world, as well as the changes that its legislation and regulations underwent. The reader will be able to appreciate the evolution and competition between airlines for world markets, from 1919 to the current situation as a result of the covid-19 pandemic. Likewise, the book recapitulates the evolution of technology in terms of passenger transport aircraft, from the internal combustion engine to the turbojet.