Wind is a result of air pressure systems, which are in turn the result of heating and cooling of the air.
The Sun provides heat but with the incredibly thin atmosphere of mars it can't keep most of it and such these systems don't develop efficiently.
Sudden wind changes can happen simply with the introduction of another pressure system into an area with two or more already.
You're basically wanted to create turbulence for the pilots, this occurs in a number of ways and most often when moving between pressure systems.
Basically you need to create these systems.
A thicker atmosphere will almost certainly be a must, how you choose do this is up to you.
I would also recommend thermal reactions on the planet, mostly volcanic activity as this will create so more random patches you're looking for.