I had the privilege of flying out and back to Seattle from Salt Lake City three different times on my last trip, and we were blessed enough to see Mt. Rainier every time. I managed to snap a few photos of the great mountain as we flew by, Seattle approach and departure procedures allowing us to fly pretty close to it (a safe close) every time.
The first photo is a shot looking towards the east as we flew by after takeoff from Seattle. It is in the afternoon so we got an appropriately lit picture (with a little help from Camera+, an excellent iPhone camera application, that allows you to do some minor photographic adjustments right on the iPhone).
The second photo is taken looking south (if memory serves) as we flew into Seattle in the morning. The photo is taken looking into the sun, so I had to pull down the Airbus window shade in order to get any sort of photo. As you can see it gives a different perspective of Rainier.
My son, Matt, and I hope to climb Mt. Rainier some day. I think you have to take a one day ice and snow instruction course and then it is typically climbed in two days. Sounds fun!