If you want a cheap flight from Portland Oregon to New York, you've got two airlines to choose from.
New York John F Kennedy Airport is just one of the airports in New York. If you're not set on a specific airport, try changing your search from New York John F Kennedy Airport to New York to see a broader range of flights – they might be cheaper. It usually takes about 6 hrs 55 mins to fly 3942 km to New York John F Kennedy Airport.
If you're planning on going to New York during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.