Earlier quoted context omitted.
With this attitude, anything is a week long project. 1. You're making extremely optimistic assumptions about the results of your system. The translation between your simulation and reality may not be so smooth. Also jets are fast. 2. Lasers jam your system. 3. It's a difficult problem to crash a malfunctioning plane in a certain area when you are behind the sticks, let alone by doing it with a collision.
In the context of asymmetric warfare this might not be a significant issue. The offensive side need only be successful a fraction of the time, but the defensive side must be successful nearly all of the time.
That or may be people can try diplomacy for once.