AA has a challenge program in which you can become an elite (Platinum) by flying only 10K miles within 90 days. When this status expires, you'll have to re-earn it the old-fashioned way, but while it is in effect you'll earn double miles. So a good way to accumulate a few miles if you time it well. There are a few fine points about the challenge, so if you are interested, you should learn them.

While I like AA's program, if you are more comfortable with any airline in terms of service or schedule, then I'd try to accumulate miles there. Presently only AI and CO offer nonstops from NYC area to DEL. However, a fair number of one-connection options exist.

IMHO when your schedule allows you to get one night's sleep in the connecting city, that is more comfortable (and you arrive more refreshed) than any nonstop in any class. I'd rather fly two 7 hours flights in economy separated by a long sleep in a real bed than one 15 hours flight in J. The emphasis is on sleep rather than tourism, so an inexpensive bed at/near the airport will do.

Good luck.