How do the cards stack up?

Each card has strengths and weaknesses. Let's look at each:

Delta: the Gold Delta SkyMiles card from American Express

Pros:

• Free first checked bag for you and any traveling companions, regardless of whether or not you use the card to buy your tickets
• Priority boarding
• Discounted day passes for Delta Sky Club lounges — though this benefit will be discontinued in 2020
• Discounts on in-flight purchases

Cons:

• No bonus earning categories (besides Delta purchases), but this is changing in 2020, when the card will offer 2x miles on US supermarket purchases and at restaurants
• No extras (like a discount on flights, extra points, or help toward elite status) if you spend a lot on the card in a year, but in 2020 the card will add a $100 Delta flight credit when you spend $10,000 in a calendar year

United Airlines: the Explorer Card from Chase

Pros:

• 2x miles on dining and hotels, as well as on United purchases
• Two complimentary one-time United Club lounge passes each year
• Priority boarding for you and your travel companions
• Discount on in-flight purchases, Global Entry/TSA PreCheck credit
• Access to additional saver-level award seats

Cons:

• To get the first checked bag free, you'll have to use the card to buy your tickets
• The free checked bag is only extended to up to two traveling companions — that's not helpful if you're traveling with a family of four

American Airlines: the Citi/AAdvantage Platinum Select

Pros:

• 2x points on dining and gas — not just on airline purchases
• Offers a solid sign-up bonus
• Free first checked bag for you and up to four traveling companions, regardless of whether or not you use the card to buy your tickets
• Priority boarding
• $100 discount on an American Airlines flight if you spend $20,000 in a year
• Discount on in-flight purchases

Cons:

• No lounge passes or discounts
• No spending bonus that counts toward elite status