Overlook route for aircraft (8)
I believe the answer is:
skiplane
'aircraft' is the definition.
(I've seen this before)
'overlook route' is the wordplay.
'overlook' becomes 'skip' (skipping is a kind of overlooking).
'route' becomes 'lane' (type of road).
'skip'+'lane'='SKIPLANE'
'for' is the link.
(Other definitions for skiplane that I've seen before include "Long accusatory speech" , "Aircraft that can land on snow" .)