United Airlines isn't into the star component of an emerging program for displaying airline products and airfare attributes. Delta had been hoping for a standard that the industry would embrace. American Airlines hasn't publicly committed either way.
All three airlines are among the progenitors of ATPCO's Next Generation Storefront. When ATPCO began publicizing that initiative, it hyped the idea of star ratings for airfare options.
A Delta official in February said that ATPCO’s star matrix was "foundational to standardizing Next Generation . . .