And because Israel has economic incentives in place to encourage Jewish people to "make Aliyah," there is a lot of demand for travel back and forth from the large centers of Jewish population. Alot of religious Jews study in Israel for a year or more, and many others own apartments in Israel, and between them, their family and their friends, tend to travel back and forth once or twice a year.
It is really impossible to convey the spiritual tug which Israel has on American Jewry.
But from what I know of growing up as a committed (but now partially lapsed) Jew in Northeastern PA......I firmly believe that PHL-TLV will be a profitable route for US, and I give them alot of credit for implementing it (or at least taking the first steps).