Mark and I live in plane and carry on (9)
I believe the answer is:
misbehave
'mark and i live in plane and carry on' is the definition.
I can't tell whether this defines the answer.
'mark and i live in plane and carry' is the wordplay.
'mark' becomes 'm'.
'and' says to put letters next to each other.
'i live in plane' becomes 'is' (I can't explain this - if you can you should give a lot more credence to this answer).
'and' is a charade indicator (letters next to each other).
'carry' becomes 'behave' ('behave' can be a synonym of 'carry').
'm'+'is'+'behave'='MISBEHAVE'
Can you help me to learn more?
(Other definitions for misbehave that I've seen before include "Act badly" , "do like naughty schoolchildren" , "mess about" , "Conduct oneself badly" , "sin" .)