It goes straight up in flight (5)
I believe the answer is:
riser
This clue might be a double definition.
'it' is the first definition.
The definition suggests a singular noun which matches the answer.
'straight up in flight' is the second definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'goes' acts as a link.
Can you help me to learn more?
(Other definitions for riser that I've seen before include "I get up" , "found on the staircase" , "Bit of a step up?" , "Part of flight" , "Upright piece in stairs" .)