After seeing all those pictures of Chuck Yeager with the Tigershark in the early 1980s and thinking it was a follow on for the F-5 export fighter role (and a good one), I was sure (yah sure) the F-20 had been sold overseas at least someplace and then brought back to replace aging first-run F 5 USAF originals.
The Air Force and Navy even leased some Kfir fighters from Israel for a time as adversary/aggressors.
Alas, the allies that would have done well by the F-20 mostly didn't buy them because the USAF didn't. Kind of a "So it's not good enough for you but it's good enough for us? Pass" situation.
It's competition at the time was the F-16A and the USAF was all in on it so the countries that needed a fighter mostly bought that. The exceptions being those that wanted twin engines and they bought the Hornet.
While the F-20 was an amazing little fighter the mission growth potential wasn't there. The F-20 and F-16A were both point defense fighters with a gun and sidewinder. Look at what the F-16 has become in the years since, a significant platform for air to ground and air superiority. The F-20 could have never expanded to fill that. Both were supposed to be cheap fighters to replace the expensive Eagle but I'm not sure how cheap an F-16 is anymore. I think it might be the most produced fighter in history though.
The USN has run some interesting adversary platforms over the years. The Kfir's worked OK but were leased essentially for free IIRC. Now with the service a fraction of it's size a lot of those services are contracted out. Not unusual to see Drakens and Hunters on the line anymore and they Adversary squadrons are getting F-16's again. Those first generation F-16N's ended up with cracked wings pretty quickly because all they did was pull g's so they had a pretty short life in the Navy.
