Due to the United States refusal to export helium to Germany, the Graf Zeppelin II was inflated with hydrogen and therefore never carried commercial passengers.

After the German annexation of Austria in March 1938, U.S. Secretary of the Interior Harold Ickes refused to supply helium, and the Graf Zeppelin II was ultimately inflated with hydrogen.

[1][2] As the ship was designed for hydrogen, there would be additional "luxury cabins" with windows on the starboard side allowing for a total of 70 passengers (this was added to the Hindenburg over the winter of 1936–1937).

The new gondolas were slightly larger to accommodate the new exhaust water recovery system and were better insulated than those on the Hindenburg, with engine noise noticeably reduced.

6 May 1937 – The LZ 129 Hindenburg bursts into flames and crashes while landing at Lakehurst, New Jersey, killing 35 out of 97 people on board and one member of the US Navy ground crew.

Wind tunnel tests in October showed a significant decline in propeller performance of the original engine cars with the water recovery system taken into account.

Only Zeppelin Company officials and Hermann Göring were present; no other government representatives came to the christening to congratulate Eckener, and he made the speech himself.

[3] By the time the Graf Zeppelin II was completed, it was obvious that the ship would never serve its intended purpose as a passenger liner; the lack of a supply of helium was one cause.

The Reich Air Ministry permitted the Graf Zeppelin to fly "for one year until 1 September 1939 without any transportation of passengers and outside of tropical areas".

The Graf Zeppelin flew across Munich, Augsburg and Ulm, landing at the Löwenthal hangar at 1.30 PM, having flown a total of 925 km (575 mi).

25 September 1938 – Started at about 11.00hrs under Captain Hans von Schiller, lasting about 7hr and covering about 764 km (475 mi), 40 crew members and 34 passengers and technicians).

27 September 1938 – eleven hours of trip duration, on behalf of the Reich Air Ministry (RLM) under the command of Captain Albert Sammt.

There were also first successes with the Ballastwassergewinnungsanlage (a water recovery system to save ballast), such that no gas had to be valved except for about 600 cubic meters for weight off.

Additionally, members of the DVG under the direction of Max Dieckmann were on board to investigate whether electrostatic charges caused the Hindenburg disaster.

The ship was flown into the stormfront slack (gas cells under-inflated), to prevent the pressure-relief valves venting hydrogen.

After the popular vote resulted in a large majority for Hitler and the National Socialist Party many propaganda channels were used – including a Zeppelin flight over the befreiten Gebiete ("liberated regions").

Taking off on 2 December 1938, LZ130 arrived over Reichenberg (present-day Liberec), capital of Sudetenland (a German-speaking area in Czechoslovakia), timed to match Hitler's visit.

Small parachutes were thrown out with swastika flags and handbills carrying the text "Dein JA dem Führer!"

The ship flew over Cologne, Hamburg, Berlin, Leipzig and Bad Neustadt an der Saale before returning to Frankfurt at 6:18 pm on 16 June.

General Wolfgang Martini, head of the Luftwaffe signals organisation, wanted to find out whether Britain possessed a workable radar system for detecting aircraft.

With General Martini on board, the flight set course for RAF Bawdsey research station and then turned north and flew parallel to the British east coast.

Several personnel at the landing site, including Captain Heinrich Bauer, were unable to board the ship as previously planned.

This 7-hour flight covered 600 km (370 mi), flying over the air show events at both Frankfurt (at the old Rebstock airport) and in Kassel where it made a short stop-over.

[7] This alleged encounter with Spitfires is not supported by contemporary news sources, which state that the LZ 130 was intercepted by two RAF planes dispatched from Dyce Airport, a Miles Magister carrying 612 Squadron Leader Finlay Crerar and Officer Robinson, and an Avro Anson.

Graf Zeppelin cruised on up to the Scapa Flow naval base, catching glimpses of British warships through the clouds.

In the early evening the Graf Zeppelin turned back to Germany without having detected any Chain Home radar transmissions.

After a Daily Telegraph report of the flight, a German communiqué was issued on 4 August stating: ‘The airship cannot leave Germany without special permission.

There have, however, been severe storms during the last day or two and it is possible that the airship could have been blown off her course over the North Sea.’[8] On their return journey, as they neared Frankfurt on the evening of 4 August they were warned by radio that landing was not yet possible.

[7] An alternative account was given after the war by General Martini who had issued the orders for the espionage trip; he told British radar pioneer Edward Fennessy that German naval radar experiments were based on much higher frequency wavebands than the British were using, and that the scientists on board concluded that the signals which they were receiving were not connected with detection equipment.

On 29 February 1940, Hermann Göring issued the order to scrap both Graf Zeppelins and the unfinished framework of LZ 131, since the metal was needed to build other aircraft.