Knock out some facts about an aircraft (6)
I believe the answer is:
dakota
'an aircraft' is the definition.
(I've seen this before)
'knock out some facts about' is the wordplay.
'knock out' becomes 'ko'.
'some facts' becomes 'data' (I've seen this before).
'about' means one lot of letters goes inside another.
'ko' inserted into 'data' is 'DAKOTA'.
(Other definitions for dakota that I've seen before include "Mass-produced transport plane, WWII workhorse, the DC-3" , "Native Americans" , "US territory split North and South" , "US state, North or South" , "State < facts about completely stunning" .)