A hangar is a facility used for parking, sheltering, servicing, or repairing aircraft, helicopters, balloons, and airships.

From an architectural and design perspective, the term refers to specialized enclosed structures built to house, maintain, and protect aircraft. A hangar is essentially a covered space intended for the storage and upkeep of aircraft.

Major hangars are typically constructed from metal, wood, or concrete. The primary purpose of a hangar is to protect aircraft from threats, weather conditions, and ultraviolet radiation. In addition, hangars often function as maintenance workshops or even assembly sites. Another important function is concealment—shielding aircraft from detection by reconnaissance planes and satellites. Because fire safety is critical, hangars must also be designed to be fire-resistant. For this reason, they are often coated with special foam systems, including an aqueous film-forming foam (AFFF) layer, whose fire-suppressant properties have been officially certified by relevant authorities.

It is worth mentioning that in 1902, the Wright Brothers stored and repaired their aircraft in a wooden hangar.

The architectural roots of hangars can be traced back to structures with arched roofs. In 1949, Peter Pedersen met a person who had developed a design for column-free arched buildings. With his assistance, he built a large warehouse that could store a wide range of goods while protecting them from sunlight. These structures gradually gained popularity in industry and commerce, to the extent that by 1958 nearly 60 percent of their users were from industrial and commercial sectors. Later, arched-roof designs were applied to underground facilities, storage tanks, and pipeline coverings, and eventually adapted for aircraft hangars and bomb shelters. Military research centers tested each of these applications and confirmed their effectiveness. During the Vietnam War in the 1960s, hangars were used extensively to protect aircraft, serving as secure shelters for U.S. fighter jets. Today, third-generation protective hangars have been tested and approved by NATO and relevant engineering units.

Hangars have not been limited to aircraft and fighter jets. They have also been used for balloons and airships, which required much larger and more sophisticated structures. One such hangar measured 358 meters in length and 61 meters in height. Since these airships were filled with hydrogen gas, preventing any spark inside the hangar was of utmost importance. Modern hangars are often described as grand aircraft garages and are sometimes coated with radar-absorbing or radar-resistant materials.

A typical hangar consists of five main sections: a general area, workshop, storage space, administrative offices, and building utilities and equipment.

Several considerations shape hangar design, including the type or combination of aircraft to be housed, the nature of maintenance activities to be performed, and the required floor area for each functional section.

Hangar doors also require careful design. Common types include sliding doors, vertical-lift doors, bi-fold doors, single-panel doors, and others, each with its own advantages and limitations.

After the Six-Day War between Arab states and Israel—during which Israel’s air force succeeded in destroying and grounding Egypt’s fighter jets, then considered the strongest Arab air force—the idea of reinforcing hangars gained traction among military planners. Subsequently, throughout the Cold War, both NATO and Warsaw Pact countries constructed hardened hangars equipped with protection against chemical, biological, and nuclear threats. NATO defined specific standards for its hangars, including resistance to 500-pound (226 kg) bombs and later to 1,000-pound (452 kg) bombs. Other notable large hangars include the one at Thailand’s Suvarnabhumi Airport (approximately 115 × 295 × 885 feet), Hangar One in the United States at NAS Sunnyvale (198 × 308 × 1,133 feet), and the Nilton Aerodrome in the United Kingdom (263 × 115 × 1,155 feet).

The Islamic Republic of Iran has recently constructed the largest hangar in West Asia. This facility can accommodate up to seven Airbus aircraft simultaneously and is capable of performing major overhauls on all types of aerial vehicles.

It is worth noting that earlier, Iran Aircraft Industries (SAHA) had begun building a hangar north of Tehran’s Mehrabad Airport. The original design dated back to the pre-revolutionary period and was prepared by Lockheed. After the Islamic Revolution, construction resumed in 1983 under the name Fajr, with modifications and the involvement of domestic specialists under SAHA’s supervision. Today, this hangar ranks as the seventh largest in the world in terms of area.

In the early days of the Iran-Iraq War, which began with attacks and bombardments on Mehrabad Airport, several C-130 aircraft were relocated to Mashhad to protect them from enemy fighter strikes.

One pilot recalls those days as follows: “That day they told us we had to fly to Mashhad. First, the fighter jets were scheduled to take off. Dozens of armed Phantom aircraft rolled out of their hangars one after another and headed towards enemy territory to mount a decisive response against the aggressors. Since Saddam, with Western support and American AWACS aircraft, was trying to cripple our air force, we had to fly cautiously and one by one. As enemy air attacks continued, we became heavily dependent on hangars. We would pull the aircraft out of the hangar and taxi them from the runway to the ramp, but suddenly, at the sound of the siren, we were forced to rush back into the hangar. Sometimes this happened over and over again. One day, during a particularly intense air raid, we took shelter with others inside one of the bomb-resistant hangars”.⁠[1]