It locates aircraft coming or going (5)
I believe the answer is:
radar
'it locates aircraft coming or going' is the definition.
The definition suggests a singular noun which matches the answer.
This is the entire clue.
Can you help me to learn more?
(Other definitions for radar that I've seen before include "Pulsed location-finder" , "one sends out signals" , "Method of detection" , "Ranging system" , "Palindromic detection system" .)