A well-known German comedian has lines in his performance that are along the lines of "Doesn't anyone think of the jobs in the dynamite stick industry?" (in relation to suicide bomber prevention, which at the time was more of a topic than right now) as a response to German government worries that higher environmental standards for cars could cause job loss in the German car industry.
Or another point of view: You think those people can either build overpriced planes or nothing at all (paying them to do community service or work on open source projects might even be preferable)?
The US (and all countries) actually do have quite a large sector of state-planned economy. Discussions about whether a country really needs to have a military more capable than the next ten (or whatever number it currently is) countries combined aside, the actual main purpose from the point of view of most politicians is to be able to have government handouts for their constituents, military results are secondary because given the huge amount of resources spent overall they'll win anyway. But instead of calling for everything to be a "free market" (whatever that means), maybe admitting that maybe a large state sector is useful might help find other places to spend such huge sums. Right now the by far most convenient way is the emotions-laden "defense". Part of the problem is that we give politicians no other choice to use money, military is the only sector where they can get away with it. Oh yes, social spending, but that does not lead to production or research or at least not nearly on a similar enough scale, besides, it is much more under attack than military spending.