"Go up in the air" means to rise in the air. "A balloon went up in the air". "Be up in the air" is an idiom. It means undecided. "His plans are up in the air because he is waiting for answer before he makes his decision".

To leave the ground Synonyms:- Lift off Take off "up in the air" undecided uncertain

Two common uses: When using nouns: (ball / bird) goes up in the air - ball is thrown into the air or bird takes flight. When using verbs: (plans / decision) goes up in the air - plans or decision become undecided or unknown (usually from a previously planned or decided state). Similar to "Now left to chance".