You can also fly in to Washington DC. It is about equal-distance from Philly.
I can feel claustraphobic if I am stuck in the middle of a row or at a window, so an aisle seat helps me.
Watching the movies, no matter how bad, helps the time fly.
You could take the Amtrak train from from NY (or DC) to Philly, but I think that would be more of a hassle than connecting to another flight. US train service is not good generally, but the NY(DC)-Philly run is not bad.
I have flown both United and BA between DC and London, and, generally find BA to be more comfortable and roomy in Economy.