Yes, this type of move could catapult United into the "top spot". And I truly hope Delta is paying attention to this move.

Here's what I hope Delta is thinking:

There's nothing they can do to block UA/AS from making this deal. A large presence at JFK/BOS will draw regulatory issues, and EWR has historically been considered a separate market, etc. You see where this is going.

Jetblue has a cult following among its loyalists. When someone comes along and destroys a brand that you love, the first thing you say is "I will never buy from this company again". Am I right?? Now we all know that's not totally true, but these type of people/customers go through a period of distaste for the company that killed their beloved (Jetblue) brand. Will some fold right into United? Yes. But many will go looking for something new. If Delta plays its cards right and takes advantage of that short window, it could gain serious favor with (former) Jetblue loyalists and gain some high value market share. How Delta does that? Who knows. My guess is aggressive loyalty offerings and nice, new planes (321NEO, 350, 220, etc). Let's be honest, Jetblue customers love LGA/JFK/BOS. Even though UA will gain some space at JFK, they will try to consolidate some flying into EWR. Jetblue customers largely do not fly out of EWR, and won't head over there just because UA says to.

Though I feel for the employees of Jetblue should an acquisition go through, we all know eliminating competition creates stability and growth for the ENTIRE industry. A rising tide lifts all boats. At the very least, Delta will benefit from increased airfare prices.