Cryptic riddle help

[Crypticcarl]

Hi my son has a book of cryptic riddles and questions but doesn't have the answers in it and I for the life of me cannot understand them so hope you can unfurl the mysteries for me.

1- A pretty thing am I fluttering in the pale blue sky, delicate fragile on the wing indeed I am a?

2-I'm as big as an elephant, but lighter than a feather. What am I?

3- If a sponge becomes an avocado how far is it to bens pink castle?

[bookbinder]

1 butterfly?
2 cloud?

[Calibax]

2 The elephant's shadow

[mike11111]

I await with keen interest the answer to no 3.

[Calibax]

^ Ditto Mike!

[stocksman]

dragonfly?