If there were any doubt, US Airways made its stance on merchandising and partnerships very clear in its announcement today about its first quarter of 2011 financial results.
In a section of the announcement dubbed "Notable First Quarter Accomplishments," US Airways cited its distribution agreement with Expedia Inc. in which Expedia commits to offering the airline's Choice Seats on Expedia websites in the future.
In contrast, there is no mention among its notable first-quarter accomplishments that US Airways signed full-content agreements with Sabre and Travelocity in February.
Instead, although the action occurred in April, well after the first quarter ended, US Airways notes among its accomplishments that it filed an antitrust lawsuit against Sabre. US Airways stated:

Additionally, on April 21, 2011, US Airways filed an antitrust lawsuit against Sabre Holdings Corporation and certain of its affiliates (collectively, "Sabre") in Federal District Court for the Southern District of New York. The lawsuit alleges, among other things, that Sabre has engaged in anticompetitive practices to preserve its monopoly power by restricting US Airways' ability to distribute its products to its customers.
It isn't often that a travel company points to a lawsuit filing as a notable accomplishment.
Including it as such speaks volumes about some raw feelings.
The public display of venom toward Sabre isn't surprising when you recall that US Airways issued a press release in early March to challenge a Sabre press release of a few days earlier and the way it characterized their rekindled partnership.