I just stumbled across footage of a German news show from April 1, 1963.
They showed LH's AIR BUS Service they started on that day between FRA and HAM.
The footage is quite interesting, unfortunately only in German: (Start at 12:16)
For those of you who don't know: LH started a commuter service between these two airports 3 times a day. The idea was to use the aircraft like a bus - no reservations necessary. The Price was relatively cheap but there was no service on board.
LH used their Super Connies on this route since they became obsolete due to the "jet clippers" used on north atlantic tracks.
The break even of this service would have been achieved by selling 50 tickets a day, but with only 37 sold in average, LH cancelled the service after a year or so.