Southwest vs Jetblue loads
Jetblue from the very early years, used a low fare, high load strategy. They had among the highest yields in the industry for a very long time. Even when they had several dozen flts on the JFK-Florida corridor they could not keep the loads below 85% to 90%. They did not want to raise the prices as they wanted to preserve the brand perception of a LCC ("value").
Southwest has not had to focus on loads but played with fares and yeilds to succeed. Frequency has been important to them from their inception, which means load factors are secondary as long as the route is profitable.
The current ligher loads on Southwest are only viable because of their fuel hedges. Jetblue made some wrong bets (senior executives have confessed to not using fuel hedges at the right time). WN can fly a 60% flt at the same price point profitably that B6 cannot on identical routes due to significantl lower costs. Wait another 2 years and WN will be in the same dilemma that B6 is in.
To maximize RASM, B6 pushes loads to the max by offering real low fares on a few seats. Alternate strategy, is to minimize the number of low fare seats and focus on more "business" passengers.
Southwest will not enter routes that require one or two round trips a day. B6 starts most new routes with 1 or 2 round trips a day. Southwest believes in high-frequency, stimulatory effect on markets. B6 seems to focus on underserved cities/markets.
As you can see with recent schedule changes, Jetblue is slowly building up frequency and connecting its network stronger. Service is being launched between city pairs that were not previously served by non-stop flts.
Jetblue is still only a sixth of Southwest. It will be much harder for Jetblue to expand nationally unless legacy carriers retreat even more to international routes.