It should be also noted that T4 is the only semi-private, non-airline operated terminal group to be selected by the Port Authority of New York & New Jersey to operate a terminal at JFK.
JFKIAT LLC, which operates Terminal 4 at John F. Kennedy International Airport, is wholly owned by Schiphol USA, Inc., a subsidiary of Schiphol North America Holding Inc., an indirect subsidiary of NV Luchthaven Schiphol, a Dutch company based in Amsterdam. (They run AMS airport, one of the better run airports in the world.)
And let's not forget that NW's partnership with KL & Schiphol Group paved the way for this expansion.