World War II brought new life to the airline industry as many airlines in the Allied countries were flush from lease contracts to the military. Foreseeing a future demand for civil air transport, airlines invested in air travel and when wartime travel restrictions ended, passenger travel around the world surged to new levels. New carriers emerged, and new technology began to revolutionize civil aviation after the war. Flying become more popular and commonplace due to the new level of speed, comfort and efficiency airlines brought to the traveling public. The jet engine revolutionized air travel, by allowing aircraft manufacturers to build bigger, faster, and more productive airliners, thus enabling them to reduce their operating costs and airfares.