As far as I know, the world's most foremost producer of
model rockets. (at least,
Estes model rockets are the only ones I have ever seen or owned, although I know that there are other companies)
Estes is based in Colorado (in the U.S.), and has been producing model rocket engines since 1958, and model rockets since not long after that.
Visit their web site at www.estesrockets.com - look at their catalog! Buy their rockets! (they're fun for the whole family...)