How do airline joint ventures affect my miles?

The short answer is that a joint venture with antitrust immunity—like the one Delta and Aeromexico just won back in court—is the strongest form of airline partnership. It lets carriers coordinate schedules, pricing, and revenue as if they were one company. For you, that means more seamless bookings, better award availability on partner metals, and the ability to earn and burn miles on either airline's flights with fewer restrictions. The appeals court ruling overturned a DOT order that would have broken up this decade-old arrangement, so for now, the status quo holds: you can still use Delta SkyMiles or Aeromexico points on transborder routes without worrying about a sudden split.

What the ruling doesn't change is that each program still sets its own award charts and fees. If you were planning a trip to Mexico, you can keep earning and redeeming across both carriers, but check the specific rates on each side—Delta's dynamic pricing may charge more miles than Aeromexico's fixed chart for the same seat. The court decision simply preserves the framework; it doesn't guarantee a good deal.

For a broader take: joint ventures are generally good news for frequent flyers because they increase the pool of award seats and make partner travel feel more like flying one airline. But they're also fragile—politics or trade disputes can upend them, as this case shows. If you're stockpiling miles in a program that relies heavily on a single joint venture, diversify your earning across alliances or transferable currencies like Chase Ultimate Rewards or Amex Membership Rewards, which give you options if a partnership sours.