The perks of Delta and Starwood’s crossover program just got a bit sweeter. Last week, the Atlanta-based airline announced that it would start adding free Comfort+ upgrades to the benefits that it gives to top-tier members of Starwood’s Preferred Guest (or SPG) loyalty program.

With no direct elite status on Delta, Platinum members of SPG (earned after 25 stays or 50 nights) can thus now enjoy first class upgrades (when available), priority check-in and boarding and a free checked bag in addition to Comfort+ seating — all without ever setting foot on a plane prior to their flight.

The benefit also extends to members of Marriott’s top tier (Platinum) Rewards members. Earlier this year, Starwood and Marriott surprised their loyalty program members by allowing them to migrate elite status and points across programs. Many have taken advantage of this capability and crossover programs between Delta and Starwood or United and Marriott to extend their benefits from one carrier across multiple partner operators.

A mid or top-tier member of United’s Mileage Plus program, for example, can sign up with the Marriott crossover program to earn mid-tier Gold status with Marriott. That status then translates to Gold status on Starwood, which earns some benefits with Delta Skymiles (though Platinum members earn more).

The expansion of Delta’s Crossover program may be part of a wider campaign to woo more business travelers in parallel markets. American, Delta, and United have all made cuts to their loyalty programs in the last years in an effort to trim out budget flyers and focus on higher-spend, lucrative travelers. By reaching out to elite members in other markets, the airlines may be able to build up their loyalty ranks again with better-targeted customers. And thanks to the Starwood-Marriott link, those benefits may be fairly widespread.

René’s Points, a blog that focuses largely on changes to Delta’s SkyMiles program, noticed the benefit initially this Friday and has more details on the upcoming relationship.

Photo Credit: Delta's Comfort+ seats. The airline is extending some benefits to top-tier members of Starwood and Marriott's loyalty program. Delta Air Lines