1. Lucy met Frank three weeks ago and fell madly in love with him. She’s been walking on air ever since.
2. If Bruce gets accepted by Harvard Law School on a full scholarship, he will be walking on air.

Synonyms: on cloud nine; seventh heaven. The expression is always used in the present participle form. The past tense is formed by using “was/were” and the future tense is formed by using “will be. ”