ballooning

中文： 热气球运动、膨胀、飞航

1. The act of something that swells or expands. (countable, uncountable)
2. The sport or hobby of flying in a hot-air balloon. (uncountable) · When he retired, he took up ballooning.
3. The mechanical kiting used by spiders, mites, caterpillars, etc. to travel through the air. (countable, uncountable)

复数 balloonings