Correct spelling, explanation: fly is an irregular, commonly used verb. The past tense of fly is flew and the past participle is flown. It originates from Middle English flogen, flowen. This is one of those forms that must be learned. The only right version of this word is flown, not flewn.

Definition of flown:
verb (past participle), to move through the air using wings
The birds have flown over my head, so I was a little scared.
I’ve never flown a plane in my life.

Collocations with flown:
Some most commonly used collocations include: have/ has flown away, have/has flown around, and have/has flown out of somewhere.

Incorrect spelling, explanation: this form is a combination of the past tense flew and the past participle flown. This word is just a misspelling, although many learners and even native speakers of English can get confused. Before writing this word, we have to remember that this is not the correct form. The only correct version is flown, not flewn.