Domestic flights? (6)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">domestic flights?</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stairs that I've seen before include "Means of ascent/descent" , "Series of steps" , "Way between floors" , "A flight of indoor steps" , "Ascending flight of steps" .)