Excerpted from Army History bulletin No. 17, Winter 1990/1991, Eyes in the Sky: A History of Liaison Aircraft and Their Use in World War II by Herbert P. LePore.

The nascence of fixed-wing aircraft in a combat milieu took place in the early days of World War I when both the Allied and Central Powers used single-engine aircraft for aerial observation. It was during World War I that aircraft technology was developed to meet the tactical exigencies of the war. Machine guns and bombs were placed on airplanes, and this meant that death and destruction no longer emanated strictly as the result of hostile action on the ground.

Although fighter and bomber aircraft flew the majority of tactical sorties in World War I, observation aircraft nevertheless played a most significant role, especially for ground commanders. In December 1917 General Henri Phillipe Petain, French commander of the Allied armies sent a memo to the commander in chief of the American Expeditionary Forces in France, General John J. Pershing, giving his opinion on how observation aircraft should be used. He stipulated that observation aircraft should be used primarily for the adjustment of artillery fire, including counter-battery fire, and for liaison missions, but not for reconnaissance purposes. The question as to what constituted observation vis-a-vis reconnaissance caused a degree of polemic at the time.

World War I ended on 11 November 1918. Besides bringing death and destruction to much of Europe, World War I served as a portent of how future wars would be fought. As an adjunct to that war, the airplane acquitted itself only too well as an inanimate “merchant of death,” and thereby guaranteed its participation in subsequent wars.

The Clouds of War and the Genesis of Organic Army Aviation

During the 1930s and at the outbreak of hostilities the United States was anything but prepared for war. One way to do this was by military maneuvers in 1941 and early 1942 to test extant and new battlefield tactics.

In the summer maneuvers of 1941 the Army tested commercially built aircraft which unofficially were called liaison or “L” aircraft, and which in April 1942 were officially designated as liaison aircraft. This was done to eliminate confusion as to who would perform what mission. These small, two-seat single-engine airplanes were equipped with two-way radios. The crew consisted of a pilot and an observer. Commercial aircraft companies such as Piper, Taylor, and the Stinson Division of the Consolidated Vultee Aircraft Corporation built the liaison airplanes used by the Army Ground Forces during World War II. The Piper Company build the ubiquitous L-4, which was the primary aircraft used during the war. Taylorcraft manufactured the L-2 and [Aeronca the] L-3. Consolidated Vultee produced the L-5 in 1943, which the Army Air Forces used in conjunction with the Army Ground Forces for the “Horsefly” mission. These various “L” planes were what the Army needed for its ground forces. They were inexpensive to operate; performed well aerodynamically; and could land practically anywhere, which caused them to be given the sobriquets of “puddle jumpers” and “grasshoppers.”

World War II and the Use of Organic Army Aircraft

Early in 1942 the Army established the Department of Air Training at Fort Sill, Oklahoma and in June of that year began to organize organic Army aviation. The Department of Air Training’s primary function was to train pilots to fly fire adjustment missions for the field artillery. Known as Class One and comprised [of] 19 students, the class completed its training and graduated on 18 September. The first five classes at Fort Sill were composed of officers and enlisted men from the Army Ground Forces and the Army Service Forces. During 1943, however, the Army discontinued bringing enlisted men into its organic aviation program because the Army’s personnel needs were such that qualified enlisted men were being sent to officer candidate schools to fill vacancies in branches such as infantry, armor, and artillery.

World War II Combat Initiation of Liaison Aircraft

The initial use of Army liaison aircraft in combat during World War ll took place in North Africa. 0n 9 November, 1942 three L-4s under the command of Army Capt. Ford E. Allcorn took off from the deck of the aircraft carrier USS Ranger, positioned off the coast, to participate in the invasion of North Africa. The L-4 crews took off from the carrier without difficulty and were instructed to maintain radio silence until they arrived at their destination, a landing strip near the coast. They were airborne only a short time, however, before they suddenly came under antiaircraft fire from the ships of the invasion fleet, whose gun crews believed they were firing at German airplanes. Still maintaining radio silence, the L-4s took evasive action and proceeded toward the assigned landing strip.

A number of problems surfaced during the North African campaign regarding the use of Army liaison aircraft. One significant problem was the shortage of these planes. There simply were not enough to be used for artillery spotting. Coupled with this apparent paucity was the fact that these aircraft at times were used for other missions, such as command, control, and communication, thereby precluding their use for much-needed artillery adjustment.

The North African campaign served somewhat as a test bed for other uses of liaison aircraft such as wire-laying, medical evacuation, and supply drops, and for command, control, and communications purposes. Deployment of liaison aircraft initially was at best desultory because ground commanders were not given ready accessibility to them and also were often not certain of how best to use them.

The Army Ground Forces and Army Air Forces Conflict in World War II

The Army Ground Forces and the Army Air Forces tended to be at times rather disputatious toward each other during World War II, especially concerning the use of liaison aircraft. The Army Air Forces had never been favorably disposed to the Army Ground Forces’ having organic aviation units, believing Ithat the Army Air Corps should be totally responsible for all the Army’s aviation requirements.

In view of the fact that the Army Air Forces and the Army Ground Forces were essential elements of the Army, their seeming lack of comity was predicated not so much on the intraservice rivalries as on their divergent ideas concerning doctrine. For example, in early 1944 Commanding General of the Army Air Forces General Henry “Hap” Arnold and Commanding General of the Army Ground Forces, Lt. Gen. Lesley J. McNair, became embroiled in a controversy about whether liaison aircraft should be under the hegemony of the Army Air Forces. General Arnold used the North Africa and Sicily campaigns as examples of what he thought to be the misuse of L-4s in combat. He stated that General Spaatz believed the Army needed a liaison aircraft that had higher performance capabilities than the L-4, and also that there should be better coordination between ground commanders and aircraft providing close air support.

General Arnold emphasized that liaison airplanes should have no less than 100-horsepower engines, which would more closely align them with tactical aircraft. He got his wish with the inception of the 190-horsepower Stinson L-5 liaison aircraft into the Army Air Forces inventory in the spring of 1944.

General Arnold further promoted the idea that if the Army Air Forces assumed control of the artillery spotting and liaison missions, it would allow the Army Ground Forces to relinquish the responsibility of having to provide men and aircraft for artillery adjustment, when the Army Air Forces could obviously perform this mission with its personnel and planes.

On 16 February 1944, General McNair issued a rebuttal. He stated that contrary to General Arnold’s opinion concerning control of organic Army aviation, it was imperative that the Army Ground Forces retain control of its own aircraft, because ground commanders could better determine the use of liaison aircraft assets than could air forces commanders.

On 25 July 1944, while watching American Eighth Air Force bombers providing close support to American ground forces near St. Lo, France, General McNair was killed (along with a large number of American soldiers) by bombs dropped too close to the American lines as a result of a miscalculated drop zone.

Observation aircraft, using skis, preparing for takeoff from a Belgium pasture (December 1944).

Later in the summer of 1944 the War Department reviewed the arguments of the two commands and after careful examination of the allegations and facts accepted the premises of the Army Ground Forces.

The Horsefly Missions

In the spring of 1944 the L-5 Stinson observation aircraft was introduced into the Italian campaign. The Army Air Forces procured a large number of these aircraft for use as an adjunct of the close air support mission. Faster and more powerful than the L-4, the L-5 could take more effective evasive action against antiaircraft fire and other aircraft than the L-4 and had greater range.

A number of L-5s were flown by Army Air forces pilots with Army Ground Forces pilots as observers who would direct by radio American fighter-bombers (P-51s and P-47s) on strafing and bombing runs to designated ground targets. Conversely, these missions were also flown with Army liaison pilots at the controls and with Army Air Forces pilots as observers. The operations in Italy, known as “Horsefly” missions, were quite successful.

The Final Drive: The Use of Liaison Aircraft in the European Theater of Operations

The role of liaison aircraft in combat in Europe was markedly expanded after the Normandy invasion of 6 June 1944. From that day to 8 May 1945, liaison airplanes proved their mettle in the Allied armies’ drive across Central Europe. They performed 97 percent of all artillery adjustment missions in the European Theater of Operations. The aircraft were also responsible for a high percentage of battlefield observation missions.

Liaison pilots found that fields and farm roads in the European terrain served well as makeshift landing strips. During the months of June and July 1944 the fluidity of the battlefield was such that liaison pilots, attempting to return to the landing strips from which they had earlier taken off, often found their original strips in the hands of the enemy.

Better coordination between artillery batteries and spotter aircraft brought quicker response times to fire mission by ground commanders.

Artillery spotter plane takes off from rice field in the Philippines (January 1945).

During World War II, particularly in Europe, liaison aircraft pilots had to deal with the threat of enemy aircraft. L-4s and L-5s were no match for the swift, deadly German ME-109 and FW-190 fighter aircraft they might encounter. In addition, the German Army High Command put something of a bounty on American liaison aircraft. Luftwaffe pilots were awarded various of air medals and points for American airplanes; the most prestigious air medals and points were given to those fliers who destroyed liaison aircraft. During 1944 and early 1945 a number of L-4s and L-5s were lost to German fighters and antiaircraft fire in the advance across France and into Germany. The liaison pilots were at times able to use a degree of aerial chicanery against enemy aircraft. When set upon by ME-109s or FW-190s, the L-4 and L-5 pilots would fly as slowly and low to the ground as possible, thus forcIng the pursuing plane(s) into a stall from which recovery was almost impossible, or causing the enemy pilot to disengage rather than risk not being able to pull out of a dive. Liaison pilots aIso attempted to lure German fighters over American lines where they would suddenly encounter antiaircraft fire. In actuality, the best defense liaison planes could muster was that of total avoidance of enemy aircraft if possible. Discretion was the better part of valor.

As the Allied armies moved towards the German heartland, Lt. Gen. George Patton, Commander of the American Third Army, entertained the idea of using a number of L-4s and L-5s to airlift infantry across the Rhine River to capture a bridge and establish a beachhead on the German side.

The Use of Liaison Aircraft in the Pacific War

As in the European Theater of Operations, liaison aircraft performed a significant role in the war in the Pacific. Warfare in the Pacific was predicated primarily upon island-by-island amphibious operations, supported by extensive naval gunfire and aerial bombardment. This meant that L-4s and L-5s often were brought ashore in crates after the landing beach or strip had been secured and then unpacked and assembled. Some of the liaison aiaircraft used In the amphibious operations were flown off jury-rigged flight decks on converted Navy tank landing ships (LSTs) which had sheets of steel matting placed over the decks as seaborne runways. L-4s and L-5s were then able to take off fairly easily. Once airborne, however, they could not land back on the LST’s deck.

Liaison aircraft taking off from makeshift runway on an LST during Anzio landing (January 1944).

The use of LSTs as airborne runways for organic Army airplanes led to the introduction of an apparatus instrumental in the recovery of aircraft flown off these vessels. Named after its inventor, Navy Lt. James Brodie, the Brodie Device was used during the battle of Okinawa in April 1945. It consisted of four masts extended over the water from the deck of an LST and was supported by a strong horizontal steel cable. A trolley with an attached sling underneath ran along the cable and, in turn, the sling caught a hook attached to a moving L-4 or L-5. If properly arrested by the sling the plane would stop immediately in mid-air and could then be lifted to the deck level of the LST and hoisted aboard. A specially reconfigured LST launched and retrieved a number of liaison planes off its deck during the Okinawa campaign without either loss of an aircraft or a pilot. This was the only time during World War II that the Brodie Device was ever used in combat.

As in Europe, liaison aircraft in the Pacific acquitted themselves with distinction, performing a myriad of functions including the calling in of gunfire during amphibious operations.


In all likelihood, World War II has had more written about it than any other conflict. Not much has been chronicled, however, about the small, slow, unarmed, single-engine “L” aircraft flown by Army Ground Forces pilots. These airplanes added a valuable dimension to both artillery spotting and battlefield observation. They provided artillery batteries and field commanders much-needed information about targets and enemy positions and movements more rapidly than had been obtained in World War I—thereby reducing response times to mission requests for artillery support. They also served well in capacities such as medical evacuation aircraft, command, communications and control, and wire-laying. Liaison aircraft served in every theater of that conflict with distinction. Just how essential they were to the winning of World War II might be a rhetorical question; however, to thousands of American fighting men whose lives were saved by timely and accurate spotted artillery fire or who were warned in time of impending danger by liaison fliers, the little “L” planes were an extremely significant factor.

These unaesthetic-looking aircraft have faded somewhat from the corporate memory of World War II, but not entirely. So long as there are Army veterans of that war there will be anecdotes about the “grasshoppers” or “puddle jumpers” and the young men who flew them over battlefields who will never be forgotten.

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