Why are numerous aircraft shown made by the wrong company?
The aerospace industry is prone to changes. Companies which were household names yesterday like McDonnell Douglas and Messerschmitt no longer exist due to mergers and acquisitions which have consolidated the industry into less than a dozen large firms (many of them multi-national) today. I firmly believe that the company that should take the credit for an aircraft is the one which designed it, not the one which markets it one decade later but unfortunately most aircraft books and sites tend to give preference to the current manufacturer rather than the true developer. Thus, on this site you will see the original companies at the time the aircraft first entered service irrespective of whether that company exists today.
