The phrase "becoming airborne" means the act of taking off or lifting into the air. Antonyms for this phrase would include "landing," "descending," "touching down," and "settling." These contrasting terms refer to the opposite actions of becoming airborne, such as the process of bringing a flying object back to the ground or decreasing its altitude. Other antonyms could be "grounded," "stationary," or "motionless," describing a state where the object is firmly on the ground and not in the act of taking off. Understanding these antonyms is important as they help us describe and distinguish between different stages of flight and movement.