Among the reasons for the increase in tourism in the 1960s were the stable political atmosphere and the development of Bangkok as a crossroads of international air transport. The hotel industry and retail industry both expanded rapidly due to tourist demand. It was boosted by the presence of US GIs who started to arrive in the 1960s for rest and recuperation during the Vietnam War.[4] Concomitantly, international mass tourism sharply increased during the same period due to the rising standard of living, more people acquiring more free time, and improvements in technology making it possible to travel further, faster, cheaper and in greater numbers, epitomised by the Boeing 747 which first flew commercially in 1970. Thailand was one of the first players in Asia to capitalise on this then-new trend.