Between 1915-1917 the Austro-Hungarian "Versuchsgleitboot", designed by Austrian Dagobert Müller, was built and launched as the first air cushioned vehicle. See the link below for the story of Müller's craft, including photos.
Throughout the period of WWI to WWII, a number of variations were designed in several countries, which all had their own shortcomings. Beginning in 1953, Christopher Cockerell, a British engineer began developing a hovercraft which is considered the first modern hovercraft. Most hovercraft used today started with his design. See the link below for a biography of Cockerell.
How it changed the world is a topic that I can't address. The change would be in the niches that benefit from it's use.