I know the trip to Alaska can be very expensive, but that seems a little extream.
I just did the search and they rainged from 600 - 800 round trip. Maybe you clicked "First Class". I know that they jack up the prices as the salmon start moving in so book early. This applys to hotels as well.
Also try some of the surrounding airports in the Ma area. Sometimes driving an hour can save you a couple of hundred dollars.
Good Luck, it'll be a trip you'll never forget!