Updated at 10 a.m. ET on Monday, Dec. 14, 2015 A youth rides a hoverboard, which are also known as self-balancing scooters and balance boards, on Oct. 13, 2015 in Knutsford, England. (Photo: Getty Images) Hoverboards may be gaining popularity as Christmas presents this year, but they’re falling out of favor with an increasing number of big airlines....