The Free Dictionary では
Time flies. also How time flies!時間が飛んでく＝時間が経つのは早い なるほどー
something that you say which means that time passes very quickly, often so quickly that you are surprised I can't believe your son is at university already. How time flies! I never seem to manage to finish my work. The time just flies.
読んでくださってありがとうございます♪
こちらもどうぞ♪