For the trip north, fly (3,2)
I believe the answer is:
run up
'north fly' is the definition.
The answer and definition can be both related to change as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
'for the trip' is the wordplay.
I cannot quite understand how this works, but
'trip' could be 'run' (run is a kind of trip) and 'run' is found in the answer.
The remaining letters 'up' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for run up that I've seen before include "Raise the standard" , "let bill accumulate" , "Go to the top of steps" , "bowler's footsteps" , "Preparatory period" .)