Gents receiving thanks during a flight (6)
I believe the answer is:
stairs
'flight' is the definition.
(I've seen this before)
'gents receiving thanks' is the wordplay.
'gents' becomes 'sirs' (I've seen this in another clue).
'receiving' is an insertion indicator.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'sirs' going around 'ta' is 'STAIRS'.
'during a' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for stairs that I've seen before include "Way between floors" , "Ascending flight of steps" , "A flight of indoor steps" , "Means of ascent/descent" , "Flights of steps" .)