This is the 3831st most frequent Chinese word.
飛行
"Flying" or "flight."
Here, '飛行' is used as a noun referring to the act or experience of flying.
飛行是一種令人向往的體驗。
Flying is an experience to long for.
In this sentence, '飛行' functions as a noun describing the action of flight performed by birds.
鳥類依靠翅膀進行飛行。
Birds rely on their wings for flying.
This example uses '飛行' in conjunction with '飛行員', which means 'pilot', to refer to a person engaged in the action of flying an aircraft.