US military destroyed the stealth helicopter which had crashed during Osama's killing raid so that technology does not fall into hands of other people.You do know the difference between license production and copying right?When you licence produce something you pay the original company for production license for the amount of product you are making for use in this case BAE. The deal is also cleared by the US Congress to see if the project is within national interest.
if USA is willing to share military technology and designs through joint ventures then why does US military takes all the trouble of destroying crashed military war machines.
A country with evil intentions can buy few war machines and then copy it and do large scale manufacturing.