Not a subject I've a clue on but aircraft do use buses. CAN (which I've at least heard of in relation to cars) and various ARINC things have cropped up in searches.I've nothad much joy finding what's used where in my brief look though.

But perhaps this may be of interest. For a Boing 777. It looks to me as if everything goes through ARINC 629 data buses but maybe I'm misinterpreting things and I'm no electronics engineer.