JJ has done several interviews in the 60s and 70s, a really good one is inside the book by Edward H Sims "Fighter Tactics and Strategy 1914 - 1970" published in 1972 ISBN-0-8168-8795-0 [ i found mine used on amazon.com for nine dollars US ]
Chapter 8 "A Reserve Officer" is entirely about old JJ and most of it in the form of an interview. It starts:
It was a sunny autumn day in Munich, in 1968, and we got up from the table in the lounge and walked through the lobby of the Hotel Bayerische Hof, outside. Smiling, my stocky, brown-eyed companion extended his right hand. With an
auf vidershen and a bow, he turned, putting on his hat and walked briskly away. About five feet nine, a quick walker in a well-tailored blue suit, he did not look back and I followed him with my eyes until he disappeared around the corner. He was seventy-four then, the most successful surviving scout pilot of the Kaiser’s Germany. He shot down forty-eight Allied aircraft in the 1914-18 war and survived a long list of incredible experiences, having met many of the best Allied scout pilots in aerial combat.
Josef Jacobs; fifth ranging ace of the German Flying Service in the World War, probably remained at the front on flying duty longer than any other celebrated German pilot.
We talked all morning about air fighting in the First World War, and about the tactics and the great fliers of that conflict, and I thought, as the famous fighter pilot now a representative of a small crane factory, disappeared: “There goes a man poorly remembered by his country for a tremendous contribution”
“I went to the front in 1914 and stayed there for the rest of the war” ….,
It ends:
He seemed amused at my astonishment that at seventy-four, he didn’t receive a pension for his outstanding service to Germany in the war.
“You see, I was only a reserve officer.”