Funny I thought Jet Blue was avoiding the major airports like KLAX and KJFK.
Their home base is JFK.. but I think your right, because of cheaper landing fees and less delays
But I bet the kicker to this service is less frequent than the KLGB-KJFK run. Because of that, after the introductory price is gone, that fare is goign to skyrocket, putting emphasis back on making the extra 20 or so minute drive to Long Beach. Plus, you'll also notice that it is a transcon destination. All their other short-haul flights still ferry through KLGB.
BL.