> The unit production cost (the cost of building an aircraft, not including amortized R&D) for the F-22A is about 50% higher than for the F-35A.

Allow me to point out the very practical reality that the figure you're quoting was the cost to build an F-22. We haven't built one since the last F-22 rolled out of Marietta in 2012, and all the tooling has been put away (and some of it has been lost). It would certainly be possible to resume F-22 production, but the cost of the first few new aircraft would be even higher than what you're quoting because we would have to teach ourselves how to build it again, and set up all the equipment and logistics necessary to do it. That won't come cheaply.

Quite right. The comment I was replying to seemed to be saying it was a mistake to cut F-22A production way back when in favor of the F-35, and I was answering in that context. Restarting it now would require hundreds of millions in tooling costs just to get the lines going again.

The solution should be relatively straightforward. Purpose built different airframes, with relatively conservative technology. Share components where it makes sense. Manufacture lots of airframes and spares. Update components later.

The next US fighter / attack program is going to be like that. It aims a lot lower and should be more predictable. I've lost track if it's called F-X or F/A-XX or what now, and what are the split parts etc...

http://www.seapowermagazine.org/stories/20160426-f35.html

There is 3 different models of super Hornets.

1) F/A-18E Strike Fighter

2) F/A-18F FAC(A) CAS/Strike Fighter

3) EA-18G Growler

Commonality is ~80% between all 3 aircraft. They could probably make a F/A-XX based on F/A-18E/F with similar avionics, and engines based on the F135 in a larger airframe, but they could make it happen relatively economically if that was the priority.

It's not a good design in the stealth and supercruise departments.

Back in the sixties and seventies when the Hornet was designed, modern stealth shaping was not really known.

Modern airframes could be a lot more capable.

Yes, my naive reaction to reading about these planes and the maintenance requirements is that they are pushing for capabilities that are unreasonable given the available technology.

If parts were going obsolete while it was still being produced, how is maintenance going to work for the next half century? I assume these were electronics?

Well, that was part of my job. In the defense industry, it is referred to as "diminishing materials suppliers" (DMS). When a supplier decided to stop producing a part, I had to identify an alternative. Sometimes it was a drop-in replacement and this was just a matter of ordering samples and testing them on our boards. Sometimes we had to qualify new suppliers to build our custom parts. Sometimes I actually had to modify the circuits to fit a new part.

Generally, near the end of production the program makes a final buy of parts to warehouse for "spares and repairs". The typical threshold is twenty years of support. If the spares run out during the support lifetime, it is up to the customer how to handle it. Sometimes we can cannibalize other aircraft, sometimes we repeat the DMS process for the parts we ran out of, sometimes (if the customer wants to keep the aircraft flying for a while longer) we do a tech refresh and design new replacement modules with current components.