The window is a one piece aluminum framed frosted, tinted glass material. It is factory built with the frame and glass fabricated as a one piece unit, the glass is not replaceable in general. Airstream makes no other. The only way to replace it would be to remove all of the rivets which hold it in place, and fabricate some curved clear glass to fit into the original frame, then re rivet it into the door. A major job. Now, if someone already makes a framed window with another type of glass (I have not seen what AWCHIEF refers to) it would not be quite as difficult, but still, all the door glass frame rivets would have to be replaced. This also would probably require the interior door skin to be removed.
It is one of those things that Airstream does that you essentially must live with.
For years I have wanted Airstream to have a clear glass option on all windows (not tinted), but they simply don't have it. Another thing that must be lived with.