Yes there was a lot of Llama Drama

.gov and DoD use FFP extensively, but typically for things which are very quantifiable... ie a truckload of potatoes.

FFP doesn't work well at all for big military systems, because in addition to complexity those tend to spiral development as they take years, and many things change over years... adversaries, technology, geopolitics.

The challenge with FFP for big weapon systems is that the buyer has to detail *very* precisely every requirement and specification. If you miss something (you will) or requirements change (they will) then you have to negotiate change orders. Both sides tend to dig in to opposite corners on that.

Cost Plus allows for flexibility and spiral development, but of course it's also well suited for FW&A.

I'd hazard that a tanker like KC-46 was in the grey area for suitability for FFP. One one hand it's not an offensive combat system with bleeding-edge performance... basically a flying gas station. But OTH, it does operate in a tactical environment, with important systems and capes for that.

A good example is the Navy P-8 and C-40. P-8 was Cost Plus, because it's an offensive combat system. C-40 was FFP because it's a non-tactical logistics transport. Both are based on the 737.