LI and NYC are really two different (huge) markets. I don't see anyone but the real die-hards trying to get into NYC from ISP with the horrible cab & train situation. And I don't see many (snobbish) business folk from Manhattan taking WN out of LGA given the many other choices. So doing a visa versa is a huge pain. I've done it twice (LGA instead of ISP) just to maximize my day at a client and paid for it with a 90 minute limo ride home on top of having to wait 30+ minutes for the limo to arrive since the arrival schedule was so padded due to frequent LGA congestion...