I don't know the specifics for JetBlue, but in general corporate insiders will tend to sell stock on an ongoing basis; just look at insider action for other companies. They get paid partially in stock or options, which means that once their rights vest, their portfolios end up being very concentrated in just one stock; undiversified portfolios are seldom good. So there's a natural, ongoing selling pressure.
However, they'll rarely be able to sell all of their exposure, as part of the compensation may be deferred stocks or options, so their portfolios will remain exposed to their own stock.
You can only derive signal value from large deviations from trend in insider action, and even that is not a reliable indicator. However, if everyone in management dumps all of their eligible shares, then you might reasonably be able to conclude that something bad is happening.