Flying and deciding on route - no good leaving separately (8)
I believe the answer is:
aviation
'flying' is the definition.
(I've seen this before)
'deciding on route no good leaving separately' is the wordplay.
I cannot really see how this works, but
'on' is present in the answer.
This explanation may well be incorrect...
'and' acts as a link.
Can you help me to learn more?
(Other definitions for aviation that I've seen before include "Flying in general" , "The aircraft industry" , "Air travel" , "Job; date" , "Aircraft operating business" .)