Why would there be? Most airlines have one issuer with cards on one network domestically, and the issuer pays dearly for the privilege. AC has three issuers (CIBC, TD, Amex) with cards on two networks (Visa, Amex). The Chase card is a Mastercard, if you're willing to get a US card. But why do you care? Amex may have a much lower acceptance rate, but the rates for Visa and Mastercard are virtually identical.