What does "high as a kite" mean — and why is it funny?

informal

Meaning

Extremely excited or euphoric; also used of someone strongly affected by drink or drugs.

Where it comes from

A twentieth-century phrase. The older sense of 'high' for cheerful or tipsy was simply pinned to the most familiar high-flying object — a child's kite.

Why it is funny

The mild humor is the cheerful innocence of the picture. Whatever the cause, the phrase sends the person sailing up into the sky as a bright paper kite, bobbing happily far above everyone else.

Used in a sentence

"She was high as a kite for days after getting into her first-choice university."