Learning to fly a helicopter can take 3 months of eight hour days. Changing one of your three controls requires simultaneous changes of the other two to maintain stteady flight. 

https://www.youtube.com/watch?v=WdEWzqsfeHM&list=PLNbXXMoWfR3Bf7Z77vcviPlkHtTXUlEpC

Here's a tethered helicopter for teaching:

https://youtu.be/vDnzpRVPCM4
Tom Cruise learned quickly in a crash course, and flew a complicated maneuver himself.