Airplane walkway (5)
I believe the answer is:
aisle
'airplane walkway' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aisle that I've seen before include "lateral strip" , "Way between seat blocks" , "Passageway between seating areas" , "Passage between pews" , "Extension of the nave in a church" .)