Credit Cards

Well, this has not happened to you only. Others have also faced these issues with AMEX on the American Airlines website. Just add your card to the list of available payment options in your profile, and then choose it at checkout.

The PNC Core Visa generally offers a decent credit limits as compared to Chase and AMEX. I am using the PNC credit card, so the highest Credit card limit is $10,000. If high limit is your main concern, then you should consider the other options like Chase or AMEX.

There are some luxury cards like Citi Prestige, Amex Platinum or Chase sapphire, which provide you luxurious benefits, travel credits and easy lounge access.
In case if you want to customize your perks, you choose co-branded hotel or airline credit cards.