Between 1929 and 1935, North German Lloyd's ships Bremen and Europa carried Luft-Hansa's floatplanes.
These were catapulted a couple of hundreds kilometres from the shore to speed up the delivery of mail.
Initially, the service was performed with the use of two Heinkel's unique He 12 and He 58 planes, replaced in 1932 by five double-the-range Junkers Ju 46.
In total, NGL's passengers admired the take-off 203 times. Interestingly, it seems that nobody - neither the travellers nor the companies that operated the service - was overly concerned with safety; spectators could freely stand just below a starting plane.
The only accident, sadly fatal in consequences, took place when a He 12 was lost together with two of its crew close to the final destination.