What is the sister company of the airline which serves Sauce Viejo Airport?
Sauce Viejo Airport:  It is served by Austral Líneas Aéreas. Austral Líneas Aéreas: Cielos del Sur S.A., operating as Austral Líneas Aéreas, more commonly known by its shortened name Austral, is a domestic airline of Argentina, the sister company of Aerolíneas Argentinas.
Aerolíneas Argentinas