Just finished another trip, two separate tickets, UA to B6 and then B6 to UA. United tagged my bag all the way through saying they could do it because of my “ticket and/or MileagePlus Status” which I appreciated. The return, JetBlue says it is not possible adjust a final destination or add it to an existing ticket, even if both were purchased from JetBlue.
The station was handled by Unifi, and they called their B6 contact who told them no. I am not sure if they actually cannot do it. I did email JetBlue and they said the partnership is new and still being worked out (having to buy separate tickets) which is a good excuse, but doesn’t solve the inability to interline.
I enjoy the A220 — but the crews are much more of a miss than United!