I'm amazed nobody has brought up Amelia Earheart. Like it's not 100% for sure solved but the odds are really good that they found her crash site all the way back in 1940, just 3 years after she went missing. On Nikumaroro atoll which was inside the search window they find bones that are likely matches for her navigator (bones of a male with European descent roughly the save height as the navigator) and damaged aluminum panels that likely cane from an aircraft. Without DNA the bones couldn't be proven to be from her navigator (they also lost them over the years so can't be treated now) and since the aluminum panels didn't exactly match the ones the plane was built with (they were likely from one of the repairs the plane recieved before and during the trip) the investigators decided it wasn't the crash site. However how many other planes from that era were missing in the same region with a person onboard that closely matched a know person on her aircraft.