So basically, the complications all come out of the fact that the airline (Air Canada) and the rewards program (Aeroplan/Aimia) are fully independent of each other.
I beg to differ, with all the intercompany transactions and shhh, top secret/no foreign nationals agreements between them (they even call it Long-Term Strategic Relationship with Air Canada in their annual report), that independence is not as clear as at first glance.
Again from their annual report
In addition, Aimia is directly affected by the financial and operational strength of Air Canada
I believe AC,CIBC and a UK chain account for 50%+ of Aimia's gross billings.
Whether intentional or not, this obfuscation of roles (AE/AC ping pong on aeroplan mileage issues for example) serves both companies rather well.
Just my 2 cents.