Prepared for takeoff (6)
I believe the answer is:
taxied
'prepared for takeoff' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for taxied that I've seen before include "Travelled slowly, as an aircraft on a runway" , "Of aircraft, moved slowly on ground" , "didn't use the bus!" , "Travelled slowly, as a plane on the runway" , "prepared to take off" .)