Just read another thread were that debate goes on so I figured I would toss in some perspective based on our experience from another relatively small airline that's ALPA. We (Hawaiian) are smaller (650 pilots) than JetBue yet there has been no down side from being ALPA at all. The support and resources available from ALPA National has been invaluable to us and instrumental in every contract negotiation we have had. Without it we would not have accomplished what we have, no question about it. It works, we have gone through tough concessionary times and more prosperous times, but the resources of a national union has been extremely important to preserving as much as we could during the tough times and those same resources have allowed us a very good contract that we would not have gotten with an in house union. As with any union, it's really the membership that ultimately drives the results, but don't let anyone tell you that the resources of a national union can't produce huge results.
JetBlue is here to stay, a union will not change anything except yield better working conditions and benefits for the pilot group and if you can keep the internal politics in check you'll do even better.
And this.....I can assure any JB pilot that is concerned about being a smaller ALPA carrier that it is not a problem. Those saying it is are simply wrong. I know the ALPA bashers like to spread that little bit of misinformation, but having ALPA as a resource has been nothing but positive for our 650 pilot sized airline.