Flat area suitable for an aircraft take-off? (5)
I believe the answer is:
plain
'flat area' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for plain that I've seen before include "open country" , "Unadorned; evident" , "patent" , "Unattractive - flat" , "Unvarnished" .)