Many foreign countries depend on U.S. manufacturing and technology to obtain the types of aerospace products they need, whether commercial or military. Oftentimes, there are laws that prohibit a country from manufacturing their own products whereby they will need to obtain it from a legal source.  In other cases, countries lack the necessary equipment or knowledge to manufacture these products domestically. Such technology could include software, such as on-board electronics and mainframe operating systems. They could also include hardware, vehicles, ships, and aircraft.
When it comes time to exporting a product, the manufacturing party must apply for an export license and go through the necessary checks and balances within the Department of Defense to make sure all products are correctly labeled and can be tracked in a national database.