<p>By then both Lowe and La Mountain were aeronauts in the Army of the Potomac, and each was doing his best to minimize the skills and accomplishments of the other. The two rivals were called into a meeting with Brigadier General Fitz John Porter, one of McClellan's staff officers and himself a balloon enthusiast. Porter suggested a truce in the best interests of the Union cause, and the two agreed to cooperate. La Mountain went on the payroll at the same $10 daily rate that Lowe was receiving.
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<p>In addition to his captive flights, La Mountain began a series of free-balloon missions. He would ascend to a level above the reach of enemy ground fire, drift over their lines and positions behind the lines, and then ascend to a higher altitude to catch the prevailing winds blowing back toward the Union positions. He did this four times between 4 October and 10 December 1861, soaring once as high as 18,000 ft (5,485 m) to find the wind that would return him to safety.
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<p>La Mountain's daring flights forced the development and use of camouflage techniques by the Confederates. Their commanders grasped the deep meaning of the sinister sphere overhead, and began to take pains to hide troop movements and campsites from airborne eyes.
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<p>By November, Lowe's four new balloons were ready, and waiting with 'Union' in Washington for orders. These arrived and Lowe, with his troop of aeronauts, joined McClellan's forces along the Potomac.
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<p>Late in 1861, contemporary history recorded the first use of an aircraft-carrier, specifically built for the mission. One of Lowe's aeronauts, William Paullin, was in charge of the balloon 'Constitution' and attached to Brigadier General Joseph Hooker's corps near Washington. Paullin operated occasionally from the flat deck of the remodelled coal barge, George Washington Parke Custis. It had been modified for balloon operations and carried the balloon, its windlass and restraining lines, the gas generator, spare parts and materials. The 112-ft (34-m) long vessel usually was towed by a steam tug, but for operations in shallow water it was supplied with long poles and oars.
