Delta launches 15% off award travel for its credit card holders — but there might be a catch

Delta Air Lines credit card holders, take note: The airline has unveiled a new benefit to promote its lucrative American Express cards. With the new "TakeOff 15" program, people with the Delta SkyMiles Gold, Platinum and Reserve cards will automatically save 15% on award travel on Delta-operated flights.

All three of the Delta SkyMiles American Express consumer cards included in TakeOff 15 are running elevated signup bonuses of 70,000 to 90,000 miles through March 29.

To take advantage of the benefit, cardholders can select "Shop with Miles" while searching for flights on delta.com. The 15% discount on miles will automatically appear in the search results and at checkout.

But it's unclear whether the value of the new benefit will be tempered by the airline charging higher rates on award travel overall.

For example, we searched for a flight from Minneapolis-St. Paul to Rome, and found an award ticket in Main Cabin for 120,000 SkyMiles from March 5-13 (with a layover at New York-JFK). With the new cardholder benefit, the adjusted cost was 102,000 miles.

That ticket would cost $1,198 if you were paying cash — nearly one penny per SkyMile, before the discount. With TakeOff 15, a Delta Amex cardholder in this example might see a savings in miles worth at least $180.

But we might have expected a slightly better SkyMiles redemption rate to begin with — at least 1.1 to 1.2 cents per mile, or more during sales.

If you're serious about SkyMiles and have good credit habits, the premium Delta Amex cards are worth a look. They can potentially offset their annual fees with standard benefits such as a free checked bag on Delta flights for everyone on your reservation (normally $60 per person round-trip), as well as priority boarding.

The SkyMiles Gold American Express is an entry-level card. The current introductory bonus offer is for 70,000 miles when you spend $2,000 on the card in the first six months. The annual fee is $99 after the first year.

The SkyMiles Platinum card is next, with 90,000 bonus miles after spending $4,000 in the first six months. The annual fee is $250, with at least one additional standout benefit: an annual companion pass that provides an almost-free Main Cabin ticket for your co-traveler on domestic flights.

The top-tier SkyMiles Reserve Amex is for serious frequent Delta fliers and airport-lounge enthusiasts. With a bonus offer of 90,000 miles after spending $6,000 in six months, it has an annual fee of $550, with goodies that include complementary access to Delta SkyClubs and two guest passes per year, plus an annual companion pass for a first-class or lower Delta ticket.

In addition to these consumer cards, the business versions of all three cards are also eligible for TakeOff 15.