At the end of Intestellar,
Cooper is instructed by Murph to leave and rejoin Amelia Brand on Edmund's planet.
Why does he do it secretly, stealing a spacecraft? He's following the order of someone who, if not in charge anymore due to old age, at least should have enough leverage to make the mission officially happen.
Wouldn't his chance of being successful be much higher with full navigation and technical support. He's off to a trip to Saturn, an intergalactic journey, black hole slingshot, etc. That's not exactly sneaking out with your dad's car for a road trip to Vegas.
Plus he's leaving with a small, seemingly single-occupancy, spacecraft. Does this thing have enough resources for the trip? What about hibernation equipment?