I’m firmly in the not going to happen camp, but to say that because they’re not talking about it or not hinting at it isn’t the best argument against any merger or acquisition. At B6 we were always told it was all about organic growth until out of nowhere we announced we were trying to acquire Virgin America. When that failed, we again were told we’d be sticking to the organic growth plan until one day, again, out of nowhere we were going to acquire Spirit.
This is how any M&A in any industry works. To those not deep on the inside of the companies involved nobody actually knows until it’s announced.

United is on cruise control right now, making money hand over fist and by far has the most ambitious stand alone plan for growth out of any airline, perhaps in history. Whether all those ambitious plans pan out is TBD. So far they’ve made good on a lot of promises and I don’t doubt they have every intention on making good on their plans. That said, it’s lofty and is contingent on a market and economy that is just going to hum along for the next 5-10 years. Things change on a dime.

Anyway, it’s been my experience that it’s usually what you don’t see coming that ends up happening. At this point I wouldn’t be surprised to wake up one day to find out it’s Southwest that shocks the industry and wants to merge with JetBlue. Never a dull moment in this industry.