Hi -- We are a family of four that lives in the Chicago area, and we tend to fly United or American most of the time. While we don't need an airline-specific credit card and are open to any and all possibilities, we do wish to find one that would help with two key things:

1. save on (or eliminate) bag fees
2. allow us to pick better seats (currently, about half the time, we seem to be not allowed to even pick our seats in advance, and often, the seats are not together)

Any credit cards that would fit the bill? Many thanks for your advice!