I am tring to reproduse these decals on my hovercraft but i dont lnow how to do this are there packs of letters or something

Try your local sign making shop. Alll they need are the letter dimensions, and spacing.

Something else you might think about is the various fonts available when using some computer programs. Depending on the program, and the number of fonts your machine may have installed, it isn't that difficult to reproduce them, scaling them up/down, and then tracing them onto our model. Then again, it isn't the most fun in the world to do that tracing and painting of the characters by hand, you know? Again, then again, with real life characters of that size, they are seldom 'perfect' and are done by hand anyway. (The really talented sign painters are the ones who have already made that mistake before (and remember it!) so don't do it again, or at least too often.)
- 'Doc

There are decal making kits that consist of special paper and an aerosol. The idea is that you produce the letters using the page processor of your choice and print onto the paper. You then spray the paper with a protective layer and when it dries, you have a water slide decal. Full instructiobs vary between makers. The one I tried was good with black, OK with colour on a white background.

whare can i obtain one of these kits

Testors model stuff sells these kits. They are item number 9198. Just go to www.testors.com for info. I got mine at the local hobby shop for $9.25. It's called Testors custom decal system. I've gotta add this though, you get a can of decal bonder, two sheets of decal paper for use with an injet printer, and a cheesy program on cd that is just about useless. The paper sheets are 5 x 7 inches. one white, one clear. If you have a good print shop program, you can use that vice the supplied one from Testors to design your graphics.