To spring or leap into the air; to take flight or take off (used for birds, planes, etc.).
朝、庭の小鳥が一斉に飛び立った。
In the morning, the small birds in the garden all flew away at once.
飛行機は無事に滑走路を離れ、予定どおり飛び立った。
The airplane successfully left the runway and took off on schedule.
驚いて彼はその場から飛び立つように立ち上がった。
Startled, he sprang to his feet as if taking flight from the spot.
熱気球がゆっくりと飛び立っていく光景を眺めた。
We watched the hot-air balloon slowly take off.