My father-in-law works on control systems for airplanes and I get the impression that it's based much more on testing in flight simulators than on any amount of

My father-in-law works on control systems for airplanes and I get the impression that it's based much more on testing in flight simulators than on any amount of proofs. The level he works at might be higher level though. It sounds like control systems for airplanes are fairly modular.