The Unfriendly Skies

Though now thoroughly domesticated, cheerful icons of state fairs and billionaire sport competitions, in their day balloons provoked fears and fantasies comparable to those inspired by today’s machinery of aerial warfare. The nineteenth century was the golden age of the balloon, and feverish visions of balloon-borne armies flying over the heads of their enemies captured the public imagination, long before the means existed to actually carry them out. However limited the actual capabilities of balloons, their addition of the skies to the world’s contested territory was unsettling, both to the European imagination and to the strategists attempting to foresee the new military conflicts that the nineteenth century’s industrial and technical revolutions might make possible.

It was apparent from the start, of course, that air travel would bring with it novel legal and diplomatic problems.^[1] On 27 August 1783, the Frenchman J. A. C. Charles launched the first hydrogen-filled balloon, the Charlière, from the Champs de Mars, and flew it 25 kilometers before landing near the village of Gonesse. Unprepared for the appearance of this invention from the sky, the inhabitants of Gonesse attacked it with scythes and pitchforks, then tied the remnants to a horse’s tail and dragged them through the fields until the contraption was thoroughly subdued.^[2] Soon after, the French crown issued a proclamation warning the people of the new machines and prohibiting interference with them,^[3] while in 1784 a decree required all French balloonists to get police permission for their flights. Just a year later, on 7 January 1785, France and Britain had to grapple with the possibilities of international air travel, as the first manned balloon made a crossing over the English Channel.

By the middle of the nineteenth century, ballooning had progressed to the point of military utility. During the American Civil War, tethered balloons, communicating with the ground by telegraph wires, were used for observation in static positions. The first purpose-built US military balloon, the Union, was launched on 28 August 1861. On 24 September, observers aboard it spotted for the first aerially directed artillery attack, as they targeted fire onto hidden Confederate positions in Falls Church, Virginia.^[4] The Confederates responded to aerial surveillance by developing techniques—camouflage, constructing dummy positions, blacking out their campsites at night, developing anti-aircraft artillery—that are still in use today.

Europeans also put early balloons to military use. The French first air-mailed military dispatches by balloon in 1793, and in 1794 Robespierre established the École Aérostatique in Meudon, though Napoleon was less interested in the military potential of these early devices, and he had the school closed when he took power in France. Military ballooning did not really flower in Europe until the Franco-Prussian war of 1870, when Paris was besieged after the French disasters on the frontier and balloons became the only (more or less) reliable means for Parisians to communicate with the outside world. Over the course of the 4-month siege, 65 manned balloons left Paris, carrying 164 passengers, hundreds of carrier pigeons,^[5] and approximately two and a half million letters and dispatches weighing nearly 11 tons in total.^[6] Not all of this mail arrived in a timely fashion—five of the balloons were captured by the Prussians on landing, while six landed in Belgium, two in Germany, four in Holland, and one was carried all the way to Norway before it came back down to earth. Though these balloons were an unpredictable means of transportation, even these uncertain results were a huge improvement over any prior method of communicating during a siege, and contemporary observers commented upon the boost to French morale when airmail began regularly to travel out of the besieged city.

Still, these free floating balloons hardly constituted a threat worthy of international attention, and the great powers of the day did not expend their diplomatic efforts carelessly. Towards the end of the century, however, the pace of technical development accelerated. The first steerable airship, La France, was launched in 1884, and by 1893 powered airships could fly at 23 kilometers per hour. In 1889, the French Government convened the first international air conference, which was attended by delegates from France, Great Britain, Russia, the United States, Mexico and Brazil. A second conference was held a year later in Paris in 1890,^[7] and in 1891 the first treatise on international air law was published. With turn-of-the-century experiments installing internal combustion engines onto airships by Graf von Zeppelin and Alberto Santos-Dumont, which pointed the way toward machines with the range and speed to carry meaningful payloads,^[8] the technology of flight had finally progressed to the point where it commanded military attention.

Fear of this novel medium, the air, for the most part outweighed fascination with its potential, however. As the century drew to a close, on 29 July 1899, representatives from 25 countries, including among them the United States, China, and all the great powers of Europe except Great Britain, gathered to sign their names to a treaty banning the military use of balloons. Short and direct, the heart of the treaty was expressed in a single sentence: “The Contracting Powers agree to prohibit, for a term of five years, the launching of projectiles and explosives from balloons, or by other new methods of similar nature.”^[9] The treaty simply rejected use of the air as a medium of war, refusing to even attempt to divide the world into permissible and impermissible targets of aerial warfare.^[10] Explicitly following, in its simplicity and its lack of either inspection or enforcement mechanisms, the tradition of the St. Petersburg Convention—which aimed to “fix the technical limits at which the necessities of war ought to yield to the requirements of humanity”^[11]—the treaty exemplifies a purer, simpler era of arms control. In limiting it to a five-year ban on the armed exploitation of balloon flight, however, the drafters of the treaty seemed almost to anticipate that their efforts were about to be superseded by advances in military physics, and it was permitted to expire after a single term.

A continuing declaration was proposed on 18 October 1907, but it was largely unratified by the great powers, for the world had changed in the interim, and a new technology had appeared whose potential was simply too uncertain—and too compelling—for the world to agree upon a means of regulating it. In 1903, the Wright brothers launched the first successful heavier-than-air flight. The significance of their invention initially eluded the same great powers who had been so concerned by the potential of balloon warfare, and it took five years and three rejected offers before the US War Department first contracted with the Wright brothers to build a military airplane in 1908. In that time, flying technology had progressed greatly—Wilbur Wright piloted a flight lasting more than 90 minutes by the end of that year, and 1909 saw the world’s first international aviation meet, at Rheims. Also in 1909, the French government set up the first regular training program for military aircraft pilots, and the rest of the major European powers quickly followed suit. The 20th century’s military fascination with flight had begun, and it quickly outraced the abilities of diplomacy to leash it. For those few years after 1899, however, flight and diplomacy were in almost perfect equilibrium, as flight was at the same time sufficiently threatening that it provoked the restraints of international law without being so captivating in its military potential that it overwhelmed them. In the century that has passed since 1903, however, that balance has—sadly—not yet been restored.