MATLAB documentation has a lot of autopilot system examples with complete documentation. You can use the links below as a starting point and then explore further.
- https://www.mathworks.com/help/control/ug/fixed-structure-autopilot-for-a-passenger-jet.html?searchHighlight=autopilot&s_tid=srchtitle
- https://www.mathworks.com/support/search.html/videos/matlab-and-simulink-robotics-arena-autopilot-development-using-model-based-design-1542699160920.html?fq=asset_type_name:video%20category:simulink/supported-hardware&page=1