The military is famous for using busy work to occupy people's time during the long periods of waiting. Do you think in that context busy work has value aside from the actual work? If so, then maybe the same principle applies generally.
>"Do you think in that context busy work has value aside from the actual work?"
No, I don't, because I don't think standing armies are a good thing. I'd rather most people in the military were trained (with re-training on a periodic basis) but were otherwise left to pursue their own interests until they were called upon to defend their country. This has been normal in times past.
If an aircraft carrier is needed around the world, there's a lot of time to fill while the ship steams into position. Even in the middle of the war, there's a lot of waiting.
What part of "I don't think standing armies are a good thing" was unclear? Aircraft carriers are useful for waging wars beyond national borders, but far less useful for defending the borders of your own country. Without a standing army, the odds of fighting a war of aggression against another nation are likely to be drastically reduced. In other words, manning aircraft carriers is not necessary.
Furthermore, in war the situation is different, standing armies are trained armies ready to deploy at all times, not just in times of war.
Wouldn't it be better to free people from having to work rather than generating a large volume of work for work's sake?