Originally Posted by
ISTFlyer
Aeroplan would be a nice option for you as you're based in Canada but that won't give you lounge access on domestic flights.
Aeroplan (Altitude) status above 35K has domestic lounge access. Above 50k (which is also *G) has access to all Maple Leaf Lounges (other than the LHR arrival lounge).
UA does not grant United Club access on domestic itineraries.