It's disappearing because your clipping distance is too short...not 100% sure where the option is, but it's in Window->General Editors->Settings and Preferences.
Look around in there and increase the far clipping range.

Unless you want a massively long nurbs plane, i suggest you attach the camera to a motion path, and just have it loop along the path. This involves going into the graph editor and setting the curve to cycle-infinity once you have the camera attached.
You'll also need to make the beginning of the path and the end relatively the same so it flows, and doesnt look like the scenery has changed dramatically.
also, there's a setting when you assign a motion path to have it follow the curve of the path...so if you set that it can appear as though the camera is swaying and swerving more naturally instead of just looking straight all the time.
Do a search for motion paths on the internet for more information.

you can also slow down the speed at which you'removing the camera and just add a lot of motion blur. it iwll appear as though the environment is moving faster than it is. that way you don't loop so often, and it won't seem as repetative.