In mid-1937, the Germans were doing experimental trans-Atlantic mail service using float planes.  The planes flew between the Azores (Horta) in the east to New York (Port Washington) in the west.  See this web site.  The catapult ship in Port Washington was the “Schwabenland” shown below.

The German ship, Schwabenland.  Note the float plane ready on the catapult.  The catapult was used to allow greater payload.

Several types of planes were used.  This is the “Aeolus” seaplane.

This is the “Zephir” similar to the “Aeolus”.  The stated purpose of all this effort was for mail service between Europe and the America’s (which included Brazil).  I’m sure there were other motives driving this as well.  Keep in mind that WW2 was only a couple of years away.

Two float planes were also used.  At the time, they were the largest float planes in the world.  “Nordmeer” and “Nordwind”.  “North Sea” and “North Wind”.  The engines were actually diesel for greater range.

My parents (before they were parents) on board the “Schwabenland”.  The Germans were happy to show off their technology in the late 1930’s.