Evidence supporting:

UA pulled out of JFK, so there is greatly diminished direct "overlap". Considering that UAL and CAL mutually did the same thing with mainline flying in the year prior to the official merger announcement it could appear that the pieces are being moved around with an "end state" in mind.

Evidence against:

AK and VA apparently can't get their merger past DOJ/DOT...at least in the present form as the deal keeps getting delayed. If AK can't get the gov't to sign off on their deal, how on earth can UAL (or DAL or AA) buy anybody?

-and-

What assets does JB have that UAL could just not buy for a few billion dollars cheaper without the baggage of a merger?? (JBLU's market cap is currently $5.66B)