GPS has been in some airplanes for ages, but not always how you think. Large jets were late to the game, a handheld works poorly or not at all behind the glass windshield with the embedded heating wires. For a time the better light airplanes had a LOT better avionics than the average airliner.
GPS is pretty common now on all airplanes, but you won’t see something that says GPS in the panel on most jets as a stand-alone device like you might in a Piper. The GPS sensors that feed the flight management system (FMS) are literal black boxes someplace out of sight. You can’t go swapping out displays in a 737 like you can in a C-150, the whole thing is certified together. It was awhile before certified GPS installs were a thing in a large jets compared to light aircraft.
The driver was ADS-B, no GPS, no ADS-B 
- oddly enough jet navigation can be a lot less demanding than low and slow. At 35,000 feet over land you are always in range of several VOR/DMEs, the FMS can derive position from that. Meanwhile at 3500 feet no such luck. Over oceanic airspace they just planned for drifty INS units and you didn’t fly very close to other aircraft.