Aviation hangars sit alongside runways as the most visible infrastructure on a maintenance platform. They are also among the least understood by the general public, because they concentrate, over a few thousand square metres without any interior column, most of the structural challenges that civil engineering knows how to solve. Designing a hangar capable of housing a modern long-haul aircraft means combining a clear span of more than one hundred metres, an interior height of thirty metres, a movable door weighing several hundred tonnes, an extractive ventilation system able to handle paint solvents, an explosion-rated fire-protection system, and a load-bearing floor capable of supporting a four-hundred-tonne aircraft resting on three landing gears. All this for what looks, on paper, like a trivial function: sheltering an aircraft while it is being repaired.
This article traces the history of aviation hangars from the wooden structures of the First World War to the one-hundred-and-thirty-metre clear-span buildings constructed for very large aircraft. It details the classes of hangars in service today, explains the main families of structures and movable doors, and shows why extractive ventilation, aviation paint and fire-safety standards largely determine the final cost per square metre. It finally describes the three hangars that AéroNéo Algérie plans to build in southern Algeria, as part of a concession application currently under preparation.
From WWI airship hangars to very-large-aircraft buildings
The history of aviation hangars predates jet aircraft by several decades. The first real hangars were airship buildings constructed in Germany, France and the United Kingdom between 1900 and 1918. With lengths of two hundred metres and ridge heights of sixty metres, they were already structural feats of their time. Their reinforced-concrete arches, inspired by inverted boat hulls, distributed loads naturally and minimised the clear spans required.
The Second World War, with its heavy bombers, changed the doctrine: rectangular hangars with flat or slightly curved roofs, opening on one of the long sides through a movable door, became the new norm. English and American workshops popularised the steel truss girder, which could span fifty to seventy metres without any intermediate column. By the end of the war, hundreds of such hangars existed worldwide, and their design has remained the matrix of every subsequent generation.
The jet era of the 1950s and 1960s introduced a new dimension: interior height. The tailfin of a long-haul four-engine aircraft of the time already reached thirteen metres, and C-check or D-check operations required a working platform to be deployed above it. The doctrine then stabilised around heights of eighteen to twenty-two metres, with clear spans of eighty to one hundred metres. This order of magnitude held until the 1990s.
The arrival in the 2000s of the eighty-metre-wingspan very large aircraft pushed the industry into an entirely new class of buildings. Hangars dedicated to this aircraft feature a clear opening greater than one hundred and thirty metres, an interior height close to thirty-five metres, and a footprint often exceeding twenty thousand square metres to accommodate two aircraft side by side. Sites in Toulouse, Hamburg, Tianjin, Dubai, Doha and Singapore have built a new generation of hangars for this class, defining the current global state of the art.
Hangar classes: light, narrow-body, wide-body, very large aircraft
The operational classification of hangars is based on the wingspan and length of the aircraft they must accommodate, which in turn determine clear span, interior height and door width. Four classes emerge from international practice.
Light class: business and general aviation
This first category groups hangars intended for single-engine piston aircraft, light turboprops and business jets up to medium-haul size. Wingspans remain below eighteen metres, clear spans range from twenty-five to forty metres, interior height rarely exceeds eight to ten metres. These are the most economical hangars to build because their structures can be prefabricated from standardised elements. They are found on every general-aviation platform and at almost every flying club.
Narrow-body class: single-aisle medium-haul
The narrow-body class covers single-aisle twinjets of the A320 and 737 families, which form the bulk of the world fleet in service. Wingspans range from thirty-five to thirty-six metres, length is around thirty-eight metres, and the tailfin reaches twelve metres. A narrow-body hangar typically features a clear opening between forty-five and sixty-five metres for one aircraft, up to one hundred metres for two side by side. Standard interior height is fourteen to sixteen metres. This is the most represented hangar class worldwide, because it matches the largest fleets.
Wide-body class: twin-aisle long-haul
Twin-aisle long-haul aircraft, whether from the A330, A350, 777 or 787 families, feature wingspans between sixty and sixty-four metres and lengths of sixty-three to seventy-three metres. A single-position wide-body hangar requires a minimum clear opening of seventy-five metres and an interior height of twenty-two to twenty-five metres. To accommodate two wide-bodies in parallel, the span rises to one hundred and fifty metres. This is the most structurally demanding class, because it sits at the very limit of what steel truss girders can span without intermediate supports.
VLA class: very large aircraft
The VLA class, created for aircraft with wingspans above seventy-five metres, primarily covers the double-deck very large aircraft. With an eighty-metre wingspan and a seventy-three-metre length, the aircraft requires a clear opening above one hundred and thirty metres and an interior height of thirty-two to thirty-five metres to clear the twenty-four-metre tailfin and allow access to the upper control surfaces. These are the most complex and expensive buildings ever constructed in civil aviation.
Structure: cantilever, truss girder, suspended structure
Once the class is selected, the structural engineer must decide how to span the clear opening. Three main families exist.
The truss girder remains the most widespread solution. A massive horizontal steel structure, made of an upper chord, a lower chord and a network of diagonals, rests on two rows of columns on the sides of the hangar, perpendicular to the main opening. This technology has been proven since the 1940s and easily spans one hundred metres today, and up to one hundred and fifty metres with a deeper mega-structure. Its main advantage is industrial simplicity: engineers know how to size, fabricate, assemble and inspect these structures with great precision.
The cantilever is a more spectacular variant: the roof is supported by a mega-structure located only at the rear of the hangar, and the front is fully unobstructed without any corner column. This solution is preferred when interference with the movable door must be avoided, for example when aircraft wingtips frequently overhang the opening. Cantilevers are more expensive than classic truss girders, but offer unmatched operational flexibility. Several recent VLA hangars combine both principles.
The suspended structure uses cables or tie-rods descending from one or more vertical pylons to support the roof. This typology remains rare in aviation because it requires very specific foundations and tensioning expertise. It has nevertheless been chosen for a few iconic hangars in Asia and the Middle East, where architectural considerations outweighed pure industrial optimisation.
Doors: sliding, telescopic, bi-fold
The door is the heaviest and most constrained moving element of an aviation hangar. On its own, it accounts for fifteen to twenty-five per cent of total building cost. Its design conditions the entire facade architecture and drives structural choices that ripple through the whole building.
The sliding door is the oldest and most widely used. It consists of several leaves that glide laterally on rails at floor and roof level. When open, the leaves park on the sides of the hangar, requiring lateral building extensions equivalent to half the opening width. For a one-hundred-metre wide-body hangar, that means fifty additional metres of building on each side. It is the cheapest solution but also the most demanding in terms of footprint.
The telescopic door precisely addresses that drawback. Several leaves nest into one another as the door opens, so that lateral extension is reduced to a single module. This solution has become the modern standard for wide-body and VLA hangars, because it drastically limits footprint while allowing openings greater than one hundred metres. It requires a very precise synchronisation mechanism and a powerful drive system.
The bi-fold door works on an entirely different principle: it articulates horizontally in two or three sections that fold upward, garage-door style. Widely used for business-aviation hangars and some narrow-body hangars, it fully clears the opening width without lateral extension. Its limitation is height: above twenty metres, the weight of folded sections becomes prohibitive and sliding doors take over.
Interior height: why twenty-two to thirty-five metres for a wide-body
The interior height of a wide-body or VLA hangar is not dictated by the aircraft’s silhouette at rest, but by the maintenance operations that take place inside. A long-haul twin-aisle tailfin reaches eighteen metres above the ground. Yet C-check and D-check inspections require working platforms to be deployed above the rudder, and overhead cranes to carry, at roof level, components such as landing gears, turbine blades or fuselage panels weighing several hundred kilograms.
In practice, a simple rule applies: interior height must exceed the tallest expected aircraft tailfin by at least four metres. For an eighteen-metre wide-body, that gives twenty-two to twenty-five metres. For a VLA with a twenty-four-metre tailfin, the figure rises to thirty-two or thirty-five metres. This additional height is also needed to integrate crane rails, industrial lighting, ventilation ducts, foam sprinklers and thermal fire-detection cameras.
Facades: ribbed metal, glazing, ETFE membrane
Aviation hangar facades fulfil three often contradictory functions: weather-tightness against rain and wind, maximum natural light to limit lighting consumption, and mechanical resistance to pressure cycles caused by door operation.
Ribbed steel or aluminium sheeting remains the most economical and widespread solution. Installed in large vertical or horizontal panels, it easily handles standard climatic loads and allows rapid construction. Its main limit is the complete absence of natural light: a fully metal-clad hangar consumes between four hundred and six hundred kilowatt-hours per square metre per year just for interior lighting.
Glazing, typically used as an upper-facade band or in zenithal sheds, brings the natural light needed to halve lighting consumption. It does, however, raise major thermal issues under hot climates, because it transmits solar radiation directly inside the hangar. Modern solutions combine solar-control double glazing with adjustable outer louvres.
The ETFE membrane (ethylene tetrafluoroethylene) has been the great revolution of the 2010s. This transparent polymer membrane, weighing less than two kilograms per square metre, can be stretched over steel frames in large panels of ten to twenty metres and offers a ninety-five per cent light transmission. It resists ultraviolet radiation for more than thirty years, does not oxidise, withstands significant thermal swings and self-cleans under rainfall. Several recent VLA hangars have adopted it for their roof or facade bands, with significant cuts in lighting electricity consumption.
Ventilation and extraction: paints, solvents, dehumidification
A heavy-maintenance hangar is not a mere shelter: it is an industrial environment loaded with volatile organic compounds (VOCs) from aviation paints, degreasing solvents, lubricants, hydraulic fluids and composite-repair resins. Without ventilation, the indoor atmosphere becomes flammable and toxic within hours.
International doctrine sets the minimum air-change rate at six volumes per hour during normal operation, and up to twelve volumes per hour during painting. For a four-hundred-thousand-cubic-metre VLA hangar, that means an extraction flow of around five million cubic metres per hour, equivalent to the ventilation of a small town. Modern systems combine high extraction through motorised roof turrets, low make-up air through wall grilles, and particle pre-filtering to avoid releasing pigments into the atmosphere.
Dehumidification is the other major challenge. Modern aviation paints require a dew point below ten degrees Celsius during application, otherwise coating adhesion is compromised. Under humid climates, this means installing chemical-desiccant or condensation air-handling units capable of removing several hundred litres of water per hour from the hangar atmosphere. Under a Saharan climate, by contrast, natural humidity is already within paint specifications, which is a major economic and energy advantage.
Fire-safety standards: NFPA 409, EN 12101 and the Algerian framework
Aviation hangars are classified worldwide as high-risk industrial buildings, because of the simultaneous presence of kerosene in aircraft tanks, VOCs at varying concentration, lithium-ion batteries on certain equipment and flammable hydraulic fluids. Three main standards coexist.
In the United States, NFPA 409 « Standard on Aircraft Hangars », published by the National Fire Protection Association, defines four hangar groups based on area and height, and requires for the upper groups a high-expansion foam extinguishing system able to submerge the hangar interior in less than sixty seconds. Stored foam volume is measured in thousands of cubic metres.
In Europe, EN 12101 on smoke control and the EN 13565 series on foam systems address the same problem, with sometimes less strict prescriptions than NFPA but equivalent reliability requirements. Wide-body and VLA hangars built in Europe generally combine both frameworks to satisfy national authorities and international operators alike.
In Algeria, the applicable framework is defined by Ministry of Housing orders and by the technical prescriptions of the Civil Protection service, complemented by the ANAC (National Civil Aviation Authority) requirements for buildings located on airport premises. For heavy-maintenance hangars, common practice aligns either with NFPA 409 or EN 13565 depending on the industrial partner, which ensures international recognition of the safety file.
Construction cost: fifteen hundred to three thousand euros per square metre
The final cost of an aviation hangar varies by a factor of two depending on building class, door complexity, interior equipment level and geographic context. The table below summarises the ranges observed in recent international practice, for turnkey buildings excluding heavy interior equipment (overhead cranes, mobile platforms, workshop tooling).
| Hangar class | Max wingspan | Interior area | Interior height | Indicative cost |
|---|---|---|---|---|
| Light (business aviation) | up to 18 m | 1,000 to 2,500 sqm | 8 to 10 m | EUR 1,500 to 1,800/sqm |
| Narrow-body (A320 / 737) | 36 m | 4,000 to 6,000 sqm | 14 to 16 m | EUR 1,800 to 2,200/sqm |
| Wide-body single (A330 / 777 / A350) | 64 m | 9,000 to 12,000 sqm | 22 to 25 m | EUR 2,200 to 2,600/sqm |
| Wide-body double | 2 × 64 m | 18,000 to 24,000 sqm | 25 to 28 m | EUR 2,400 to 2,800/sqm |
| VLA (very large aircraft) | 80 m | 15,000 to 22,000 sqm | 32 to 35 m | EUR 2,600 to 3,000/sqm |
These ranges cover structure, movable door, facades and roofing, standard foundations, ventilation, lighting and basic fire protection. They exclude workshop fit-out, which can represent twenty to thirty per cent of final cost on its own, heavy access pavements, and digital hangar-twin equipment. The cost per square metre decreases as area grows, which drives operators to design multi-position hangars rather than several stand-alone buildings, provided industrial workflow supports it.
“The modern hangar is no longer a mere aircraft shelter. It is a complex industrial machine, whose performance is measured in available square metres, in lumens of natural light, in cubic metres per hour of air renewal, and in seconds of extinguishing-system response.”
AéroNéo: three hangars planned in southern Algeria
As part of its integrated aviation-platform project in southern Algeria, AéroNéo Algérie plans to build three hangars on the area to be granted under concession. The planning is indicative and will be adjusted in line with the final specifications validated with the ANAC and local authorities, and with the industrial partners joining the project.
The first hangar would be a double-position narrow-body hangar for base maintenance on single-aisle aircraft of the A320 and 737 families, with a clear span of around one hundred metres and an interior height of fifteen metres. The second would be a single-position wide-body hangar sized for a long-haul aircraft of the A330, A350 or 777 class, with an eighty-metre clear span and a twenty-four-metre interior height. These two buildings would cover the majority of operator needs for C-check and D-check visits across North Africa and the Sahel.
The third hangar is still under opportunity study. It could be a dedicated paint hangar with high-performance extraction and filtration, or a second wide-body hangar dedicated to passenger-to-freighter (P2F) conversions, whose long immobilisation cycle would justify hangar positions separate from base maintenance. The decision will be made when the business plan is finalised, depending on industrial-partner commitments and ongoing market-study conclusions.
Architectural design will draw on the most recent international standards, with particular attention to energy performance under the Saharan climate. The significant solar resource of southern Algeria will be leveraged through integrated photovoltaic roofs covering a meaningful share of hangar electricity consumption. ETFE membrane facade bands are also under study, to reduce artificial-lighting consumption during daytime hours.
The planning schedule remains subject to progress on the concession application and to the signature of industrial agreements currently being negotiated. AéroNéo Algérie is in a pre-launch phase and communicates on strategic orientations without committing to service-entry dates. The technical elements presented in this article reflect current international doctrine and will serve as the basis for engineering choices to be formalised once the concession perimeter is finalised.
Conclusion: a structure at the crossroads of civil engineering and aviation doctrine
The modern aviation hangar is, in the literal sense, an industrial work of art. It combines the structural challenges of a one-hundred-and-fifty-metre bridge, the thermal constraints of a tropical greenhouse, the ventilation requirements of a chemical plant and the safety standards of an oil depot. Its design mobilises multidisciplinary teams of structural, thermal, fluid, electrical, fire, automation and architectural engineers, who work together for twelve to eighteen months before construction begins.
For a country such as Algeria, installing wide-body and VLA hangars in the southern Saharan region is not a simple property operation: it places the national sector within the narrow circle of global platforms able to host every class of the commercial fleet. This ambition is at the heart of the AéroNéo project, whose first buildings will, in time, shape the industrial silhouette of a new African aviation hub.
