Chris, you didn't say where you live or what airports are near you. If you live in St. Louis there is a neat situation, there is a parking lot for spectators at west end of main runway, and it is on a hill that overlooks the runway. I have gotten some neat night shots there.
If you live in a city with a major airport downtown or with high buildings not too far from airport, you can occasionally get good shots from that kind of building/airport arrangement. It is suprising how little angle you need. After all, on final approach the planes are flying towards the runway at only a three degree angle, so even a fraction of a degree is often adequate!