These things typically have a skirt made of rubber on their bottoms.  
Charles J. Fletcher invented one of these devices during World War II, but he wasn't allowed to patent it because the US Army classified the invention.  A museum devoted to these things in Lee-on-the-Solent, England contains examples of them such as the "snazzy" 1980s-era Canair.  The first practical one of these things was called the SR.N1, was developed by Saunders-Roe, and was accidentally given a "royal dent" by the Duke of Edinburgh.  A prototype for one of these things was built by placing a small aluminum can inside of another one.  That proof of concept also featured a (*) vacuum cleaner and was designed by Christopher Cockerell.  Types of these things include the LCAC used by the US Navy.  These things typically have a skirt made of rubber on their bottoms.  For 10 points, name these vehicles capable of traveling over both water and land.
Charles J. Fletcher invented one of these devices during World War II, but he wasn't allowed to patent it because the US Army classified the invention.  
Hovercraft [or air-cushion vehicle or ACV or glidemobile]