If you look at how the F-15 came to be, NASA did a lot of the initial aerodynamic work. Engine wise, there were multiple suppliers (although not initially). No

If you look at how the F-15 came to be, NASA did a lot of the initial aerodynamic work. Engine wise, there were multiple suppliers (although not initially). No fly off. For F-16 and F-22 each there were two different manufacturers with different prototypes. Both had also multiple companies co-operating. Many companies have merged since. There are some hard questions. Sometimes groundbreaking technology is developed in a company and other designs become obsolete quickly. This happened with stealth. How do you deal with this?