* very: Modifies the adjective "gently"
* gently: Modifies the verb "flew"
Let's break down why:
* Adverbs describe verbs, adjectives, or other adverbs.
* Here is an adverb of place, but it doesn't modify any other word in this phrase.
* Flew is a verb.
* Gently is an adverb describing how the subject flew.
* Very is an adverb intensifying the adverb "gently."
So, the adverbs are very and gently.