Why does CO have such huge price differencial between EWR and JFK? I routinely travel from New York to Houston, and EWR flights are always priced three to four times that of JFK flights. For e.g. EWR - IAH - EWR on 10/25 - 10/26 are price $650 + while the JFK - IAH - JFK for the same dates, and same timings are $158. The LGA - IAH flights are priced around $550 (a hundred bucks cheaper than EWR).

Why is EWR priced three / four times the price of JFK flights? The fllights are both non stop and on regular mainline planes (737's).