It is unclear to me how to reconcile the UA enhanced Class Feature Variant; Ranger Companion Option with the Beast Master Ranger’s Companion feature rules (PHB p.93).
Specifically, in the case of a 5th level Ranger who chooses a Beast of the Air. Would the Ranger add her proficiency bonus (3) to the beasts AC, attack rolls, damage rolls, saves, skills?
If yes, then what would the resulting stat-block look like for a Beast of the Air companion for a 5th level Beast Master Ranger.
If no, then please explain why the Rangers proficiency is not added.