We always seem to go on about how the load factor is irrelevant for the airline, it is the revenue it can make from it. This is so much more important for routes such as this.
There can only be a 50% load factor yet if J is full and they are all flying onto, say, LAX, then CO is laughing, opposed to 100% staying in NYC.
The beauty of a hub system - if they get the transfer passengers...