I see several ways that can be used to stop these from being hacked.
One is to have no external control of flight to destination, but have a emergency stop that can be activated by proximity sensors or sensitive areas and or police. But this is just a auto land. The navigation system will be by 2 means and they must match exactly for the flight to commence. This will have pre programed flights on its hard drive, the passenger then buys the destination flight ticket some form of app to your phone or a USB stick. This will have your GPS track and alt info. So lets say it is a USB - this destination you brought gets matched to the flight on the hard drive of the drone. The flight will then take place on that exact route with no external flight changes unless the emergency is activated - but this will just pause the flight and land.
The second would be the opposite and be more like how Bitcoin works - many computers used to verify the safe flight of all drones all the time, so many that they can not all be hacked fast enough. This would give more freedom of flight paths but be more complicated.
I don't expect there will be private people transport drones - but you may own your own capsule that the drone attaches to.
A smart government would jump on this - renewable energy on the rise!
* Sell the flights to the public as monthly subscriptions (Netflix, Microsoft, NBN - fast or slow).
* Sell capsules to the public. (A new model each year - iPhone).
* Collect data from the public.
* Reduced cost of road maintenance and upgrades.
* Less staff to employ on current public transport.