From Longman Dictionary of Contemporary Englishhot-air balloonhot-ˈair balˌloon noun [countable] 
TTAa large balloon filled with hot air, used for carrying people up into the sky
TTAa large balloon filled with hot air, used for carrying people up into the skyExamples from the Corpus
hot-air balloon• Perhaps the engine of an abandoned car will start or a hot-air balloon will materialize.• And hot-air balloon cylinders do travel by road - between flights.• Right: tethered hot-air balloon rides were popular.• The hot-air balloon skims along a wash, following the narrow line of trees and bushes across the desert. 