The first technological challenge in aviation was to construct a heavier-than-air machine with the capability to lift the weight of a man in the air and to maneuver such a carriage in different directions.

Although powerful engines were available in the early 1910s, they were quite heavy and bulky. To soar, an airplane needs a powerful engine that is both light and small. The first airplanes incorporated relatively hefty engines that could only develop enough power to lift the aircraft and the pilot. They lacked the muscle to carry loads other than the scarce fuel needed for the short trip.

In 1903 the Wright engine required 15 pounds to develop each horsepower. By 1918 the Liberty L-12A only required 2 pounds
In 1903 the Wright engine required 15 pounds to develop each horsepower. By 1918 the Liberty L-12A only required 2 pounds

Once engines with higher power-to-weight ratios became available, more fuel could be stored, and longer trips were possible. Flying provides the capability to watch the earth from an outstanding vantage point and has a fair degree of immunity from attack. As a result, the first military mission of the airplane was observation. The Italians were the first to deploy an air unit in a conflict against the Turks .

On 23 October 1911 captain Carlos Piazza was ordered to discover the location of the enemy. He carried out his mission successfully by seeing Turkish encampments and making his report upon landing since air radios did not yet exist .

Although today that mission may appear to lack glamour, the reality is that the ability to detect enemy positions and movements provides extremely important intelligence to military commanders who until then had to use foot and horse patrols or spies to obtain such information. Furthermore, evidence from these latter sources was relatively old by the time it was in the hands of the commander and reliability was often in question. Reconnaissance then became the first air mission of military value.

Inevitably, it occurred to the Italian airmen that a more direct route to influence battle was possible. Releasing light objects from airplanes was also feasible so on November 1st, Italian aircraft dropped the first bombs (actually grenades) on the Turks . Thus, the second military air mission, destroying surface targets, commenced .

Two and a half years later, when World War I started in April 1914 only reconnaissance was firmly established. But then, the first crude attempts at bombing began in August. During October the British successfully carried out the first significant mission when they destroyed the new German zeppelin in its shed . Bombing ground targets was now not only a nuisance but operationally important, so the different air forces forcefully sought means of protection.

On 1 April 1915, the era of air combat opened when Roland Garros, a French pilot, shot down a German Aviatik airplane with his forward firing machine guns. Destroying flying aircraft was born as the third military air mission .

Roland Garros, French pilot that started the era of modern air combat

Airplanes were also moving people from one place to the other but the capability to load heavy and bulky cargo was not yet there. Armies assigned low military value to this capacity during the Great War.

After World War I, airlines sprung up and quite soon newer aircraft were moving thousands of people and tons of cargo around the world, so the benefits dawned on the armed forces. This is the fourth major air mission of military value: transport.


Engineers can design an aircraft able to carry out the four missions with adequacy. In theory, this is ideal since only one airplane needs to be engineered, one type of plant is needed to manufacture it, and training and maintenance are simplified as well. Air forces would also have maximum flexibility to carry out the four missions with an existing force structure.

In practice, however, single-mission aircraft have an edge, since they need to meet fewer compromises and thus they can excel in their area of specialization .

The mission of reconnaissance airplanes is to observe enemy-held territory to detect and evaluate the adversary’s strength, location, disposition and capabilities in the broadest possible sense. Based on this information it is possible at times, to infer the enemy’s plans and activities. They do so, by reconnoitering zones where armed forces are engaged in combat and zones behind the front, in many cases deep inside the enemy country. The ultimate intent is to find opportunities that can be exploited by friendly forces.

The purpose of aircraft devoted to destroying targets on the ground or water is to annihilate the enemy’s capabilities identified by reconnaissance or other forms of intelligence . Destroying, damaging or neutralizing these targets negates at least temporarily its use by the enemy. At worst, the threat of destruction forces the enemy to allocate resources to defend important targets, so even lack of damage does not imply necessarily complete wastage of effort.

Bombers carry out most missions of this type but attack planes using guns and rockets play an important, although subsidiary part. A sub-specialization of bomber aircraft is the torpedo-bomber whose aim is to destroy vessels. Less frequently, transport airplanes have been used to neutralize key targets using paratroopers or air-transported infantry . Note that in this case, these cargo aircraft are the means to deliver the weapon (soldiers) to neutralize a target.

Fighters are designed to shoot down enemy airplanes . This destruction is the means to gain air supremacy in a volume of airspace. If achieved, friendly forces can use that airspace to carry out their air missions without fear of heavy losses and at the same time, the enemy is prevented to operate unless prohibitive losses are accepted.

Transport airplanes or cargo airplanes move friendly resources from one geographic point to another where they are needed. It is a logistical rather than a combat mission, except when deploying paratroopers or infantry.

The Four Basic Air Missions
Mission # Mission Name Mission Purpose Type of Aircraft Used to execute the mission
1 Reconnaissance Observation of combat zones and zones of the interior to evaluate the enemy’s strength, location, disposition, plans and capabilities to find opportunities for own side.
Spotter planes can also direct artillery fire to improve accuracy
Reconnaissance and spotter
2 Destroying surface (ground/water) targets Destruction of enemy’s strength-furnishing assets and capabilities on targets situated on the ground or water. Bomber and attack
3 Destroying flying aircraft Secure air supremacy by destroying enemy aircraft in the air. Once attained, it is possible to carry out friendly air missions with low risk while the enemy is prevented from doing the same. Day fighter and night fighter
4 Transport Movement of own side resources (supplies/personnel/information) to the geographic area required. Transport and liaison

These four tasks or a combination of them encompass the great majority of the missions carried out by World War II military aircraft over the fighting fronts .

Between the wars, decision-makers in charge of the air forces and airpower theorists concluded that the proper combination and execution of those missions on the enemy would bring about victory in war if enough resources were devoted to them.

The most enthusiastic of them, particularly in Italy, Great Britain and the US, were convinced that air power alone could win the war . Other thinkers, mainly in Germany, did not go that far but resolved that airpower was now more powerful than ground or naval power and therefore the most decisive of military branches .

With this belief as to the basic premise, doctrinal formulation followed. Doctrine attempts to answer a basic question: how should the air arm be employed to defeat the enemy?

This is a simple question, but the response has many layers.

LuftWaffe Doctrine
General Walther Wever (inset) provided a solid operation doctrine to the Luftwaffe. The picture shows A. Hitler and H. Goering in his funeral (1936). Bundesarchiv, Bild 183-2006-1010-503 / CC-BY-SA 3.0

The purpose of the armed forces in conflict is to apply force on the enemy so his will is broken and consequently he has to accept the will of the victor.

From the perspective of the air arm it is necessary to establish the most effective way to maximize such application of force: Who is going to apply what force and against whom?

The Chief of Staff of the Luftwaffe, Walther Wever, ruled that a decisive victory could only be attained if the army, navy and air force applied force in a coordinated fashion within the framework of a common strategy. He identified the main target of this applied force as the enemy armed forces and not the civilian population .

Using the four basic air missions as building blocks, he then defined a shortlist of operative air missions that the new Luftwaffe could realistically carry out productively:

1. Attainment of air superiority
2. Support of ground forces
3. Support of the navy (or independent war at sea)
4. Interdiction of enemy communication to and from the battlefield
5. Strategic actions to neutralize sources of military power (destroy the enemy industrial capacity)
6. Attacks against enemy cities to break the enemy morale (only as retaliation) or against military targets (government and administration, military commands, and training centers)

Missions 2 and 3 are fought over the battle zone while mission 4 is fought in rear areas. Mission 1 occurs over both zones. Missions 5 and 6 are carried out over the enemy’s zone of the interior (beyond the battlefield zone and rear areas).

Since the enemy targets are likely scattered over enormous expanses it dawned on him that only by concentrating the air assets on critical areas and selecting similar types of targets at a time, could the Luftwaffe achieve important results.

It was only logical that the Germans endeavored to engage in conflicts where decisive victories could be attained at the least possible cost of casualties and time.

The Blitzkrieg method of warfare was the result of careful design by German military theorists and Wever meticulously integrated the previous operative air missions into this scheme.

The Luftwaffe High Command (OKL) decided to fight the future battles and campaigns sequentially:

1. A decision in the air must precede a decision on the ground, so the priority was to achieve air supremacy over the critical areas.
2. With air superiority attained, the air force would focus its efforts on direct and indirect support of the ground forces. The emphasis was on the second: interdicting enemy communications and thus isolating the battlefield.
3. Strategic targets would be attacked last.

Each of the operational missions can be drilled down further. For instance, in the case of the support of the ground forces (number 2) the following tactical missions were identified: (a) air reconnaissance for the army, (b) protection of ground troops and facilities from enemy air attacks and enemy reconnaissance, (c) attacks on ground targets in the battle zone and rear zone, and (d) air transport, liaison and courier services . The Luftwaffe developed specific tactics, equipment, training and methods for each of these tactical missions to execute them with effectiveness.

Luft Waffe Doctrine
Luftwaffe Doctrine

The OKL also established that in this scheme the bomber was the most important air asset, but other types of aircraft played an important role to guarantee success. As a corollary of this critical conclusion, the Luftwaffe force structure was carefully balanced to manufacture, train and deploy:

40% bombers (one-quarter of them single-engine and three-quarters two-engine)
30% fighters
20% reconnaissance
10% transport

Luftwaffe’s principle of concentration of force dictated that the air assets should be concentrated in time and space. Instead of flying missions all over the front attacking any attractive target, they were massed along with the points of maximum effort to form a bubble of air superiority over the battlefield zone and the enemy’s rear areas. Most of the bombing missions were against enemy airfields and interdiction in the rear areas to isolate the battlefield preventing reinforcements and supplies from coming in and preventing retreating forces to escape.

The targets in the rear areas were ideal for the capabilities of the bombers at the time and had the following characteristics:

• Compact (intended target was tightly clustered)
• Visible from the air
• Sufficient size (if the target was too small, accuracy would suffer. Bridges, supply columns, and railroad marshaling yards had sufficient size for a productive attack)
• Weakly defended (the rear area was a large region of space and it was impossible to defend it strongly everywhere)
• Suitable for destruction (the types of bombs available could destroy or damage the targets)

Attacks in the battle zone were second in priority and the density of tonnage dropped by the Luftwaffe was less intense. The targets in this sector were less appropriate because of the following traits:

• Dispersed (troops and vehicles in the battle area were spread out to minimize losses)
• Difficult to see from the air (either, the enemy troops would be under camouflage or it was difficult to distinguish friends from foes)
• Targets were too small (individual tanks, vehicles, guns or squads occupy a very small sector)
• Area heavily defended (most of the anti-aircraft weapons and small arms were present in this area)
• Suitable for destruction (if bombing accuracy was adequate, they could be destroyed)
Manu of the targets in the enemy zone of the interior presented some advantages:
• They were compact
• They were visible from the air as long as sufficient intelligence was gathered on them (to minimize effects of camouflage)
• Adequate size to hit them accurately
But some of them also presented special difficulties:
• Very well defended (unescorted bombers need to fly long distances over hostile airspace)
• Difficult to destroy (factories can be repaired soon or dispersed quickly to restart production)
By focusing on profitable targets, the Luftwaffe proved able to exert very significant force on the enemy helping to secure victory on many occasions.