Answer 1
In the early 1950s, much faster commercial jet aircraft came on the scene and drastically reduced the travel time between continents.
Answer 2
Sustainable tourism is tourism that, according to the Brundtland Commission definition of sustainability, meets the needs of the present without compromising the ability of future generations to meet their own needs. Fundamentally, sustainable tourism is tourism that contributes to economic, environmental, and sociocultural impacts, which benefit today's stakeholders while also enabling future generations to achieve the same positive impacts.