John D Collins on Jun 30, 2015
Proceed on Course instructs the pilot to intercept and follow the previously assigned course or route. This usually is after a vector for spacing, traffic, or other reason. It does not permit the pilot to select any route or course, but just the one that the aircraft was previously cleared for.
Resume own navigation applies to ending radar vectors and permits the pilot to chose their course or own navigation. So you are VFR and using flight following services. ATC instructs you to fly a vector for traffic. When the traffic is no longer relevant, the controller would say “Resume own navigation”. You can chose your own route.