That is Buck Mountain in the background. The Grand Teton is to the right, blocked by the tail of the airplane or just out of the frame. It's hard to make out from this angle, but there is a peak just below and to the left of Buck Mountain. I climbed that peak back when I was 20. That's been a few years.
UPDATE: My parents picked us up at the airport. Having arrived early, they headed toward Grand Teton National Park to kill some time. When returning to the airport my mom spotted our plane coming in for its landing -- and snapped these shots:
In that second photo, you can see Jackson Hole Ski Resort above the plane at about 1 o'clock.