If the plane flies itself, it should also monitor itself. Humans aren't well suited to the role of hyper-vigilant overseer of a long, monotonous, fully-automated process.

Yes, they should still be there to apply judgment when something exceeds design parameters. But any process that can be made hands-off needs to have robust automated monitoring built in. Executing the plan is a fine goal, but it's much more important that you know whether you're executing the plan.

Monitor first, automate second. Otherwise, you're just building a method to execute mistakes faster.