Originally Posted by
cjgibson
Probably because the 777 from LHR becomes one of the flights to Asia. The 752s aren't going anywhere other than back to Europe (or maybe LAX, IAH, or Florida), so they're not needed back in EWR so early.
Or there is significantly more demand on a slightly later flight, so they use the 777 there. Or a combination of the two.
This way they cater for any demand for an early morning flight, and then have a 777 to cover the large volume of people that want to travel mid-morning.