Gazes fixedly, flight being heard (6)
I believe the answer is:
stares
'gazes fixedly' is the definition.
'flight being heard' is the wordplay.
'flight' becomes 'stairs' (I've seen this before).
'being heard' indicates a 'sounds like' (homophone) clue.
'stairs' is a homophone of 'STARES'.
(Other definitions for stares that I've seen before include "Long gazes" , "Looks hard" , "Looks fixedly" , "Looks lengthily at" , "Assert with long looks" .)