When Rainwater asks for the Fish And Wildlife environmental impact report, he states he wants to see what the impact of an airport beside the river that feeds Yellowstone National Park. But the Yellowstone River does NOT flow into Yellowstone National Park. The Yellowstone River's source is Yellowstone Lake, which is in the south-eastern quadrant of the park. From there it flows north into Hayden Valley, the Grand Canyon Of The Yellowstone, then northwest, where it exits the park near Gardiner, Montana.