During the planning phase of Operation Barbarossa, General Thomas' pragmatic and realistic nature once again gripped him as he thought a full-scale war with the Soviet Union should be delayed until the logistical concerns were remedied. Along said lines, Thomas informed Colonel-General Franz Halder, then Chief of the OKH General Staff, that the attack on the Soviet Union would experience logistical delays due to the fact that Russian railways were of a different gauge than German ones. Thomas also warned Halder of the insufficiency of German transport vehicle tires for the task ahead of them, and most significantly, Thomas revealed to Halder that they (the Germans) only had two months worth of fuel oil and petrol to support the advancing assault. Inexplicably, Halder did not convey this information to Hitler and when Thomas attempted to do this himself, General Field Marshal Wilhelm Keitel stepped in and prevented the report from going any further. Reassurances soon made their way to General Thomas when no less than "Reichsminister" Hermann Göring told him not to worry about using up Germany's resources since "they would soon be masters of France, Belgium, and Holland", likewise adding that they would plunder all the available resources in the "captured territories".