Really interesting idea and concept! I think it definitely could use a bit more polish around feedback and controls (mouse controls would be amazing), and it'd be nice to be able to queue up a bunch of flight paths and then "start" the construction, because with the ships starting immediately, it makes the game kind of confusing and hard to keep track of. The most fun is definitely planning the routing and trying to make your ships do the "right" thing, so building the gameplay loop to support that idea makes the most sense to me.
But when you nail the build order and just get to watch the item factory, it's really satisfying, and a lot of fun! Great work on this game!