Posters on this board should consider that Doug Parker has messed around with Chapter 11 quite a bit. AWA, US, and AA were all in chapter 11 at one time or another, and he was involved in their emergence. What Doug did was "do a deal" to attract outside money.
Virgin Atlantic is in bankruptcy (chapter 15 I think they call it over there) but as part of the reorganization they will maintain their arrangement with Delta. 51% British and 49% Delta owned. Delta has cash on hand and they will pony up to keep the arrangement.
In the early 90's, Then US Air attempted a link up with British Airways under the same type of arrangement.
https://www.latimes.com/archives/la-...469-story.html
Watch for a revival of that deal. It will be done to attract outside financing and with Brexit, BA still retains tremendous route authority all over the world. AA pilots will not want to share international flying but Parker will attempt something like this to save his legacy and avoid another chapter 11 filing.