I had bags like that when I delivered the early morning Indianapolis Star in junior high school 1966--68.
They go much further back-
before I could fit it and was still on a 20" Sting ray (reformed from the 20" inch bike under the Christmas tree a few years earlier), Dad bought home a very old and in need of reconditioning old balloon tire bike I ended up calling the Old Green Clunker. That was about 1964. He painted it green and got some middle weight tires and got it going before I could straddle the top bar- had a Western Flyer crank as I later recalled
but the unique thing about it was both a rear clunker luggage rack and two steel loops that came out over each side of the back wheel- Dad's best guess was that it was to keep bags like this outta the spokes- But what it was was the perfect place for someone else to sit on the luggage rack and place their feet- "trailing" we called it-
and within a year or two some of us in the neighborhood had devised an activity we called "The Pony Express" where one kid would ride the bike up to and past another who hopped on the back "seat" and into the steel loops. From there- without stopping the rider moved back on one side of the Old Green Clunker, and the "trailer" kid moved up the other side until we had switched positions- then the original rider hopped off and the other kid rode on- really stupid, but it later helped me do exchanges in the Little 500 I think
In 1967 I won a bus trip trip to Detroit for selling newspaper subscriptions where we toured the Ford plant, visited Greenfield Village and saw the premiere of Grand Prix in Cinerama. Quite the trip for an eighth grader.