I have my dad's USAF pilots knife from Vietnam (He was Navy CB- go figure) and bought another from a guy in Kennesaw about 10 years ago for $10 shipped. They're great knives with good steel, come with a sharpener, a good sheath and are even made to be lashed to a pole for a spear.
They are great!
-But the steel is hard to sharpen. I bought a set of nice lansky diamond stones and worked and worked. It is sharp now, but it took a long time. My cousin has a knife sharpening machine with a big belt and it wouldn't touch that hardass steel.