The GPL only states you have to release the source to people you distribute the code to, not directly make it publicly available. If the missiles work well enough when "delivered", there will be no one left eligible to demand access to the source!
Assuming that they are not selling them to someone rather than firing them at someone, of course.
This is sort of hilarious, but I'm pretty sure that firing a missile at someone doesn't count as giving them code. Its not your intent that they're able to use the missile for their own purposes, for example.
Your intent isn't important - it's the intent of the person licensing the software.
I publish my shark+laser beam integration library in the hope that other evil geniuses will use it and improve on it. Together we can produce an opensource shark+laser beam system that is more secure and reliable than the commercial offering. When you are an evil genius you have to worry about these things.
Assuming that they are not selling them to someone rather than firing them at someone, of course.