Eyes in the Sky
Richard P. Hallion
Airpower shaped the early battles of World War I, with profound consequences.
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Air & Space Forces Magazine
Over the fateful summer of 1914, Europe plunged into the abyss of war. Before it did, government officials, military experts, and popular journalists spent weeks tallying the strength of nations and their war-making potential. They calculated power based on the density and strength of fortifications; the number, caliber, and range of cannon; divisions of fielded troops; and the tonnage, armor, and throw-weight of ever more imposing dreadnoughts.

Only a few thought of airplanes. Compared to forts, cannon, ships, and infantry, the frail wood, wire, and fabric “aeroplanes” seen buzzing through Europe’s summer skies seemed hardly more consequential than darting dragonflies.

Yet prewar maneuvers had already convincingly affirmed their potential as flying scouts, and all of Europe’s leading armies and navies already possessed some. An average two-seat airplane of 1914 vintage weighed about 1,600 pounds, had an 80 horsepower engine, could reach an altitude of 9,000 feet, attain 70 mph, and remain aloft up to 3.5 hours. It would be outperformed by all but a handful of today’s general aviation airplanes and remotely piloted aircraft.

Armies and navies typically assigned six to 12 airplanes to divisions, headquarters, ships, and ports. Observers—generally staff intelligence or cavalry officers—directed their pilots, took notes, and snapped photographs. Though a few airplanes had crude wireless sets, crews more typically scribbled terse messages and dropped them to friendly ground forces, or landed in clearings or on roads near their parent units to report firsthand.

Austria-Hungary declared war on Serbia on July 28, and by the end of August the war had spread from Europe to the Middle East, Africa, Asia, and even the islands of the far Pacific. Besides the Hapsburg monarchy, the major combatants at the war’s beginning were France, Germany, Great Britain, and Russia. Among them, they could field more than 400 divisions. As well, they possessed over 900 aircraft: 176 French, 208 British, 256 German, and 268 Russian.

Targeting the French

In 1905, Field Marshal Alfred von Schlieffen, the chief of the Oberste Heeresleitung (OHL), or the German high command, had declared that in any future war, “the French army must be annihilated.” He envisioned the German army smashing through Belgium into France, thus evading its frontier defenses, sweeping southwest of Paris, then looping back to roll up the French army in disarray. After he retired in 1906, Schlieffen’s basic plan lived on. Consequently, by mid-August, five German armies were poised to invade France.

France, however, had a powerful ally: Russia. For two decades, uneasy with Kaiser Wilhelm II’s bellicosity, the two countries had formed a mutual assistance pact. Now, France’s ambassador in St. Petersburg begged Czar Nicholas II to order an immediate offensive, warning, “There is a risk of the French army being overwhelmed.”

Nicholas agreed. Russian headquarters subsequently ordered General Yakov G. Zhilinsky to prepare for an offensive “at the earliest possible moment.”

Zhilinsky commanded the Northern Army Group, consisting of two armies of 200,000 troops each, with supporting artillery and cavalry, and approximately two dozen scout aircraft, most of French origin.

Defending East Prussia was the German 8th Army. It numbered about 150,000 regulars and aging reservists and could call on some 40 reconnaissance aircraft distributed in eight flying detachments. Prudently, the 8th Army commander on Aug. 2 ordered his airmen to reconnoiter the Russian border territories.

For two weeks they flew as far as Kovno (now Kaunas, Lithuania) in the east and Mlawa, Lodz, and Warsaw to the south. Though weather aborted some missions and some missed Russian troops already employing camouflage to evade detection, overall, the airmen discovered a surprisingly rapid Russian buildup. Concerned, on Aug. 14 Field Marshal Helmuth von Moltke, chief of the army supreme command and Schlieffen’s successor, warned the 8th Army commander he must conduct “an offensive defensive” when the Russians eventually attacked.

They would have three advantages: a document found on a dead officer at Gumbinnen disclosed the basic Russian strategy; sporadic radio intercepts offered some significant operational tidbits (though not perfect awareness); and vigorous aerial reconnaissance provided tactical updates on enemy locations, threats, and possible opportunities several times each day.

German planners expected Russia to vigorously employ its airplanes, but it did not. One corps commander lamely rationalized afterward that he’d been “keeping them for a more important moment,” as if one existed.

While Russian aircraft sightings were rare, German aircraft droning overhead were commonplace. They flew multiple times each day, tracking the Russian advance even before it reached the Prussian frontier. “Every morning the German aviators would appear over our bivouacs or columns on the march,” recalled a Russian corps commander. He added, “The enemy aviators observed us with impunity.”

The payoff came on Aug. 18, when German airmen detected a gap between the 1st and 2nd Russian armies. It continued to widen, as one slowed and the other pressed onward. Subsequent signals intercepts offered corroboration that the gap was still expanding, raising the prospects of isolating and destroying each army as time went on.

On Aug. 27, after having carefully assembled his forces, Gen. Paul von Hindenburg struck, attacking Usdau (now Uzdowo, Poland), Hohenstein (Olsztynek, Poland), and other positions. Within hours, his soldiers had cut through Russian Gen. Alexander V. Samsonov’s army, halting his 1st Corps and sending his 6th Corps reeling in retreat. By the next day, Samsonov’s 2nd Army had lost all cohesion, its officers and men fighting a series of disconnected actions and having only vague ideas of the locations of friend and foe. Meanwhile, Hindenburg’s airmen kept the 8th Army routinely informed of enemy forces and dispositions.

As Aug. 28 opened, Samsonov’s separated corps were fighting against encirclement. Throughout the day, German generals received “good reports”: Troops captured Neidenburg (Nidzica), severed most escape routes, and by night, were threatening Samsonov’s encircled forces at Hohenstein with annihilation.

The next day, the ring around the Russians tightened despite, as Hindenburg recalled, a heroic resistance, “which saved the honor of arms but could no longer save the battle.” All the while, his airmen observed and updated his commanders. That night, Samsonov held a final counsel with his officers, then slipped quietly away to shoot himself in woods bordering Willenberg (Wielbark).

On Aug. 30, reconnaissance flights detected that a desperate final thrust by a corps-size force assembled from remnants of various Russian formations threatened a German corps. Continuous aerial monitoring gave its commander confidence and time to continue fighting, while his fellow leaders, hastily briefed by the airmen, dispatched reinforcements. Thus, though the column did briefly occupy Neidenburg, it lacked sufficient strength to withstand the certain German assault to follow. Pulled back, its soldiers retreated through Mlawa, bringing the battle to a close.

The next day, Aug. 31, Hindenburg sent a victory message to the Kaiser, announcing the destruction of the 2nd Army, the capture of “more than 60,000 prisoners” (actually, more than 90,000 were taken), adding that “the booty is immense.” Indeed, it filled 60 trains.

Later, the Germans christened the battle “Tannenberg,” pointedly recalling a battle fought over the same ground slightly over 500 years earlier. In that battle, a combined Polish-Lithuanian army had broken the power of the Teutonic Knights, a humiliation now seemingly redressed. A month later, at the Masurian Lakes, the Russian 1st Army likewise met defeat, setting Czarist Russia down a road that would eventually lead to its collapse.

A postwar US Army study found that the Russian 2nd Army never had a clear picture of German dispositions and locations, thereby suffering “a succession of disastrous occurrences, largely avoidable, had the army commander been promptly informed of events.” That’s what air reconnaissance could have furnished, had Russian commanders only appreciated it.

The victors certainly had: Hindenburg exclaimed appreciatively to air staff Maj.Wilhelm Siegert, “Without airmen, no Tannenberg!”

Marne: Victory for Airmen

But in the west, Germany’s invasion of Belgium and France was in trouble.

Various factors played a role. Moltke had modified Schlieffen’s plan, reducing the troop ratio between the offensive right wing and defensive left wing to ensure defeating any French attack on Germany. Then, defying expectations, Britain honored an 1839 treaty to defend Belgium, sending troops to fight in France. Finally, the Russian offensive had forced shifting some troops from west to east.

In early August, the first elements of Britain’s expeditionary force arrived in France. On Aug. 13, 60 Royal Flying Corps (RFC) airplanes hopped the English Channel to join them. Six days later, they flew their first combat sorties. “They kept close touch with the enemy,” Field Marshal John D. P. French wrote later, “and their reports proved of the greatest value.”

On Aug. 22 they detected troops of Gen. Alexander von Kluck’s 1st Army advancing on the Brussels-Ninove road toward a British corps commanded by Lt. Gen. Horace L. Smith-Dorrien. Unlike many of his contemporaries, Smith-Dorrien appreciated aerial reconnaissance. The sighting gave him an advantage Kluck should have enjoyed, but did not. Though, over the previous two days, German airmen had spotted the British moving toward Mons, Kluck never received the information in time to turn it into actionable intelligence. Unlike Hindenburg’s army on the Russian front, Kluck’s lacked an efficient intelligence field distribution process.

Thus, at Mons on Aug. 23, Smith-Dorrien’s corps shocked Kluck’s troops with a veritable sheet of brisk, accurate, and sustained rifle fire. Their withering marksmanship cost Kluck a day’s advance, and his army only crossed into northern France on the 25th. At Le Cateau on the 26th, it clashed with Smith-Dorrien’s corps again. French’s advisor, Gen. Henry H. Wilson, noted that the German artillery was “extremely well-served by aeroplane reconnaissance.” Afterward, the Allies continued to fall back.

Advancing alongside Kluck’s 1st Army was Gen. Karl von Bülow’s 2nd Army. On Aug. 28, British airmen detected a growing gap exposing its flank to attack. A subsequent assault by the French 5th Army so discomforted the twitchy Bülow that he immediately asked the more forceful Kluck for help, even though German air reports indicated (quite accurately) that the Allies were not only still retreating, but that they were “in disorder.” So confident of victory were German airmen that, on Aug. 30, one overflew Paris in his graceful Taube (“Dove”), hand-dropping four small bombs and a message cheekily urging surrender. “The word ‘Taube,’?” a Parisian wrote, “took on a sinister meaning.”

Desperate to win, Moltke now abandoned the Schlieffen plan, ordering all five German armies to advance in parallel southwestward in an assault on Paris. But Kluck and Bülow had decided to turn their armies east, passing north of Paris in the region of the Marne valley. This they did, on Aug. 31 and afterward, to avoid further chaos, Moltke gave his after-the-fact approval.

Early on the morning of Aug. 31, a British aircraft spotted elements of Kluck’s army moving southeast, not southwest. Subsequent flights confirmed the unexpected shift. Then, on Sept. 2, a French spotter aircraft found Kluck’s army had turned even farther eastward, with its leading elements passing well north of Paris. Incredibly, the French 6th Army’s chief intelligence officer refused to pass this information along, apparently more willing to trust reports from horse cavalry than from airplanes. Corroborating reports by French and British airman, supported by intercepted communications, eventually pushed the report forward.

For days the air-minded military commander of Paris, Gen. Joseph S. Galliéni, had awaited an assault on the city. The sightings brought both relief and opportunity: Kluck’s flank was wide open. Galliéni ordered intensive air reconnaissance for the next morning, Sept. 4, stressing its “vital importance” and the need to get the information to him “with all speed.”

Nine aircraft set out that morning, the first reporting back at 10:15 a.m. One after another, all confirmed that the Germans had indeed fatally exposed their flank. Listening to the reports, a French staff major exclaimed, “We’ve got them!” Brig. Gen. David Henderson, chief of the Royal Flying Corps, predicted the shift would be taught to future staff college classes “as one of the great mistakes of the war,” as it proved to be.

Assuming the Worst

For five days, French, British, and German troops grappled in the Marne valley, fighting the kind of frontal battle Schlieffen had explicitly hoped to avoid. The battle was not even joined when, on Sept. 5, French Gen. Joseph J. C. Joffre visited the British high command to express his gratitude to the RFC’s airmen for the “vital part” they were playing in keeping him “accurately and constantly informed of von Kluck’s movements,” furnishing him “the certainty” needed to make solid plans.

Ironically, a corrosive lack of resolve triggered Germany’s departure from the Marne. An ill-considered visit to the front by Moltke’s chief of intelligence, Lt. Col. Richard von Hentsch, sealed the deal.

Sent by Moltke to assess conditions at the front and, if necessary, make on-the-spot decisions in Moltke’s name, Hentsch was inexperienced and preconditioned by Moltke’s increasingly bleak outlook to assume the worst. He arrived at Bülow’s headquarters on the evening of Sept. 8. Their discussions that night and early the next morning reinforced their uncertainties, and Bülow, supported by Hentsch, determined to withdraw to the northeast.

En route to Kluck’s headquarters on Sept 9, Hentsch then encountered what he later related was “a complete panic.” “

En route to Kluck’s headquarters, Hentsch then encountered what he later related was “a complete panic.” A single Allied airplane had bombed the road, disrupting and delaying traffic. The five hours it took for him to travel the 60 kilometers between the two headquarters solidified his perception of disaster. Consequently, after his late arrival that afternoon, he announced Bülow was withdrawing, invoking authority granted him by Moltke to insist Kluck do as well. And so Kluck did, beginning his own retreat. Afterward, German Gen. Walter F. A. von Bergmann, the 1st Army’s chief quartermaster, castigated Bülow’s “unjustifiable decision to retreat” and Hentsch’s “disastrous interference,” writing bitterly, “All that had been gained was surrendered.” Ahead lay four years of misery and stalemate, lasting until Nov. 11, 1918.

“Our aeroplane officers are real heroes,” Smith-Dorrien recorded in his diary, as reports came that Kluck and Bülow were withdrawing. He added, “In spite of being shot at every time they go up, they continue their reconnaissances and bring back quite invaluable, and what always proves to be true, information.” Retreating no longer, RFC headquarters now moved forward to Coulommiers.

Airmen made the difference in the battles of Tannenberg and the Marne. Aerial reconnaissance furnished the crucial information to winning commanders; lack of it cost the losers their victories. The mere presence of persistent aerial overwatch influenced commander decisions that ultimately led to their defeat. Despite the passage of a hundred years, the airpower lessons learned of the Great War are as pertinent today as they were then.