What would you suggest as a more efficient way to achieve this goal? Building thousands of advanced fighter jets for private citizens? Keeping highly skilled engineers up to date on the most modern technologies and maintaining specialized factories is inherently expensive. You can't leave the factories mothballed because you need to keep the skilled workers employed and practiced with manufacturing.

Maybe there could be something like a weekend warriors but for machinists? One weekend a month, one week a year you build fighter jets. This does mean there needs to be private sector demand for those skillsets so the reservists have relevant day jobs.