Airlines are becoming adept at filling seats. The load factors (% of sold seats) are commonly in the high 80's. They now gauge the aircraft to the routes to minimalize wasted (empty) seats. You now see 737s and small airbuses coming from american hubs where you used to see 747s and L1011s 3 X bigger. There are fewer low and shoulder season flights and more companies are cooperating with each other by code sharing (selling seats on other airlines) A better gauge would be hotel occupancy and from what great deals I see offered in Negril in October I would say it is a good time to go.