Fly round with no regard to the rules but perfectly (10)
I believe the answer is:
flawlessly
'perfectly' is the definition.
(thesaurus)
'fly round with no regard' is the wordplay.
'round' indicates putting letters inside.
'with no regard' becomes 'lawless' (I can't explain this - if you can you should believe this answer much more).
'fly' enclosing 'lawless' is 'FLAWLESSLY'.
'to the rules but' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Another definition for flawlessly that I've seen is " without making a mistake".)