You can't turn off the planes, but you can simply ignore them as they come and go. The worse thing you get is the icons on the top showing the planes arriving and sitting at the airport. As for Joe just rescue him and then don't repair his plane and he'll just sit at the airport and won't bother you.

As for the Uncle you can't turn him off, but what you can do is when you help him with whatever he shows up for and then he goes to leave use the broom to flip him into the desert. Everytime you load your save you'll get the VIP Has Arrived message, but he'll never come through again, unless you use the big red button to reset all cars/customers.

Thanks for the info, will leave Joe where he's sitting at the airport and only come across for a few planes but not all.
Shame you can't 'knock' Uncle other than to strand him in the desert, but that fits in with his character.