Delta just added a major new perk to its Amex cards—and travelers are going to love it

American Express and Delta Air Lines are adding new perks to their cobranded credit cards just ahead of the busy summer travel season, including a benefit frequent Delta flyers have long wanted: a second free checked bag. The two companies announced Thursday that several Delta SkyMiles American Express cards will receive updated travel perks, refreshed card designs, and limited-time welcome bonuses for new applicants. Notably, the changes come without an increase to annual fees. The update...