I'm flying to Amsterdam in August for a cruise, and ended up booking flights to/from Philadelphia instead of JFK or EWR because it was $200 cheaper out of PHL. I live an hour north of EWR, so PHL is out of the way for me, but not enough so that it's not worth driving to in order to save $400 for the two of us.

This isn't the first time I've noticed this pricing. We flew to Barcelona a few years ago and found the same thing (that time there were 4 of us so it was a no-brainer). This time, my flights go thru DTW so I will need to end up back in PHL, but the last time they went thru JFK (and we "missed" our connecting flight back to PHL and picked up a rental car at JFK). I will probably drive my own car to PHL and park at a hotel and get a sleep/park/fly package since it is cheaper than renting a car in both directions.

Anyway, what is it about PHL that causes the fares to be that much cheaper? Is it competition from US Air? I tried looking for fares out of BDL or ALB hoping they would also exhibit the same "cheaper than NYC" behavior but they weren't cheap. Or is what I am seeing not common and I just got lucky both times?

If there is a better place for this thread, please move it.