hoverboard       
noun [ C ] uk/ˈhɒv.ə.bɔːd/ us/ˈhɑː.vɚ.bɔːrd/
 (电影或小说中虚构的)飞翔器,悬浮滑板
a form of transport existing only in films and stories, that a person can stand on and that floats a short distance above the ground
  How is it that several decades after Back To The Future Part II came out, we're still waiting for our hoverboards? 
 - More examples
 - The hoverboard took the U.S. by storm in 2015, endorsed by several celebrities.
 - Today, table tennis and hoverboards abound on the campuses of high-tech companies.
 - Recently, he mastered the one-wheel hoverboard (imagine a skateboard with one large wheel in the middle).
 - At some points in the game the player can jump on a hoverboard.