Space to stretch out (5,4)
(Other definitions for legroom that I've seen before include "Space in front of a seat" , "Space to stretch for seated person" , "Space often lacking on a plane!" , "(Seated) person's space for feet" , "Space needed to avoid cramped position" .)
(Other definitions for elbow room that I've seen before include "adequate working area" , "Freedom to move" , "sufficient space" , "Space to move" , "find adequate space to work in" .)