To use your American Express Delta SkyMiles in 2026, the most effective method is booking award travel directly through delta.com or the Fly Delta app. Simply log in to your SkyMiles account, enter your flight details, and select the "Shop with Miles" checkbox to see prices in miles rather than dollars. A major perk for Amex cardholders (Gold, Platinum, and Reserve) is the "TakeOff 15" benefit, which provides an automatic 15% discount on the mileage cost of Delta-operated flights. You can also use "Pay with Miles," a feature exclusive to cardmembers that allows you to reduce the cash price of a ticket in $50 increments (5,000 miles each). Beyond flights, miles can be used for seat upgrades to Delta Comfort+ or First Class, or for purchases at the SkyMiles Marketplace for gift cards and merchandise. For the best value, travelers often look for "Delta SkyMiles Deals," where domestic round-trips can occasionally be found for as low as 10,000 miles, especially when combined with the cardmember discount.