Finally there's American Airlines: the Citi®/AAdvantage® Platinum Select® World Elite™ Mastercard®.

Welcome bonus: Earn 50,000 American Airlines miles after you spend $2,500 in the first three months.

Annual fee: $99; waived for the first 12 months

Earning miles: 2 miles per dollar spent on American Airlines purchases, at gas stations, and restaurants, 1 mile per dollar on everything else

Top benefits: Free checked bag on domestic flights, preferred boarding, 25% off in-flight food and beverages, no foreign transaction fees

50,000 miles (or at least 52,500, when you factor in the miles you'll earn for completing the minimum spending requirement) can get you far on American Airlines — as long as you can find "SAAver" availability. Based on American Airlines' award chart, it's nearly enough miles for a round-trip flight to Europe or South America during peak season, a one-way ticket to Europe in business class, or at least two domestic round-trips (or more, depending on the distance).

The Citi/AAdvantage Platinum card earns 2 miles per dollar spent on American Airlines purchases, and Citi also recently added a few new bonus categories — new card members will earn 2x miles on restaurants and at gas stations, too. You'll earn 1 mile per dollar on everything else.

The card comes with a suite of useful benefits for American Airlines flyers.

You and up to four companions traveling on the same reservation each get a free checked bag on domestic flights (since American Airlines is a full-service carrier, most international flights include the first checked bag for free). Because the first checked bag is usually $25 each way, this benefit can save you $50 on a round-trip itinerary.

In addition, you and everyone on your reservation get preferred boarding — joining an earlier boarding zone. That gives you more time to settle in — and earlier access to the overhead bins, so that you can make sure you'll have room to store your bag.

A small, but useful new perk: When you spend $20,000 or more on the card in a card membership year, you'll get a $125 discount on your next American Airlines flight (that's in addition to the miles you'll earn on those purchases).

The card also offers a 25% discount on in-flight purchases, such as food and drinks, and access to discounted mileage award flights.