High speed flier (3)
I believe the answer is:
bat
This might be a double definition.
'high' is the first definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'speed flier?' is the second definition.
'bat' can be an answer for 'speed' (thesaurus). I'm not sure about the 'flier?' bit.
Can you help me to learn more?
(Other definitions for bat that I've seen before include "Wooden implement for cricket" , "Small flying mammal - like 11 Across" , "Night-flyer" , "Flutter (eyelids)" , "Nocturnal flier" .)