a1bill,
Focusing on the F-35 for a moment, are the "Flyaway Cost" defined the old fashion way as defined in standard US Government requirements, or the new fashion way as defined by the DoD F-35 JPO? There are differences. Matter of fact, in the new way, you can't fly away at all, the engine isn't included because it is a totally separate contract.
I became interested in "What Does The F-35 Really Cost" 3 years ago because of this series that ran in Time magazine. I don't think much has changed. Have a look, especially Part 2, Alphabet Soup: