When it comes to the subject of "lost pilots" the word lost is not necessarily accurate. A lost program or pilot refers to something that people look for and can't find. Often, lost pilots were never lost to begin with…they had always sat in the archives of the studio or network. A more accurate name for these pilots would be "unaired pilots" because they were never broadcast on network television. The main reason for this was they were never meant to air. Often, in order to sell a concept to a network a pilot will be produced. Sometimes it sells, sometimes it doesn't. Often, the pilots will be radically altered prior to the series being picked up by the network. LOST IN SPACE, THE MUNSTERS and THREE'S COMPANY all had pilot episodes that were radically different from the program that eventually aired. (Actually, THREE'S COMPANY had 2 or 3 unaired pilots before they finally got it right) These days unaired pilots are somewhat rare mainly because pilots are expensive to produce and companies do not want to be out a few million dollars if the pilot doesn't sell. This does not mean there are no unaired pilots…just less in number than they were in the past.