Altitude likewise had been obliterated. The customary height for two-seated observation and bombing planes was between one and two miles, and of single-seated scouts between two and four miles. These altitudes were not the freakish heights occasionally obtained by adventurous fliers; on the contrary they were the customary levels at which the different kinds of duties were carried out. Many men, of course, went far higher. Since then an American, Roland Rohlfs, flying a Curtiss "Wasp" set the unofficial altitude record at 34,610 feet--higher than the world's highest mountain. Life at these altitudes was not possible, of course, under ordinary conditions. The temperature fell far below zero and the air became so thin that neither man nor engine could function unaided. As a result the fliers were kept from freezing by electrically heated clothing and from unconsciousness from lack of air by artificially supplied oxygen. Similarly the oil, water, and gasolene of the engine were kept working by special methods. The armistice threw the different nations into a dilemma as to their aviation plans. Obviously the huge war planes which were still in the building in all the belligerent countries were no longer necessary. Almost immediately, therefore, the placing of new contracts was halted by the various governments, enlistments stopped, and plans set in motion for the new requirements. Within a very short time the United States canceled several hundred million dollars' worth of contracts on which little actual expenditure had been made by the manufacturers. Shipments of men and planes overseas were of course brought to an end and at the same time arrangements were made for bringing back from France the great aerial equipment mobilized there. Indeed, the air service units were among the first to be returned, especially the labor and construction troops in England. Nevertheless, military aviation of the future was definitely safeguarded. A bill was presented to Congress for an aerial force of 4,000 officers and 22,000 men, a fitting contrast to the force of 65 officers and 1,120 men with which the country had entered the war. Certain flying fields and schools which had shown the greatest value in the past and promised most for the future were definitely designated for permanent use, and especial effort was made to keep in the service the best of the technical experts and designers who had helped to solve America's problems of the air.