Flight into street-tunes (6)
I believe the answer is:
stairs
'flight' is the definition.
(I've seen this before)
'street-tunes' is the wordplay.
'street' becomes 'st' (abbreviation).
'tunes' becomes 'airs' (air can mean a piece of music).
'st'+'airs'='STAIRS'
'into' acts as a link.
(Other definitions for stairs that I've seen before include "A set of rising steps" , "Interior means of ascent" , "A flight of indoor steps" , "4 and 8 (to the cockney)" , "Series of steps" .)