It depends why those people are flying to New York or connecting onwards to the US. If they are travelling overseas for business, then that is bringing home extra revenue to the North East. If they are going for a holiday then yes, it brings little benefits to the North East directly, however it helps to keep those flights viable for those using them for business purposes.
Providing direct flights opens up new markets, and makes it easier for local businesses to conduct work abroad, and makes the area more attractive for inward investment.