There are exceptions. Air New Zealand once turned a Boeing 777 into a giant ad for Lord of the Rings, Mango, based in Johannesburg, utilises a bright orange hue, while Siberian carrier S7 tends to colour its planes lime green. But the vast majority of passenger aircraft are painted white. Why?

It’s cheaper

“Paint adds between 600-1,200 lbs (273-544 kg) of weight to an aircraft,” a spokesperson for Boeing told Telegraph Travel. Extra weight means more fuel is burned, and 544kg equates to around eight passengers.

And airlines take the issue of weight very seriously. In the 1980s, for example, Robert Crandall, the former chief executive of American Airlines, claimed the carrier had made annual savings of $40,000 by removing just one olive from every salad served on board its flights.

The paint itself costs money too, and repainting an aircraft uses a lot of it. “Approximately 120 gallons (454 litres) of paint are used on a typical 747; 90 gallons (341 litres) on a 767; and 110 gallons (416 litres) on a 777, while a typical 787 Dreamliner paint scheme involves 800-1000 lbs (362-453 kg) of paint,” said Boeing. All told, repainting a plane costs between £36,375 ($50,000) and £145,503 ($200,000).

Furthermore, airlines often end up selling their aircraft to other carriers. They will find it harder to do so if the colour scheme is anything but white.

Reducing the plane’s heat absorption as much as possible keeps cooling costs down. Credit: AP

It keeps the plane cool

In the same way that lighter colours dominate our summer wardrobes because they are cooler, aircraft are painted white to reflect sunlight.

“The main reason why aircraft are painted white or light colours is to reflect sunlight and minimise both the heating and any potential damage from solar radiation,” R. John Hansman, Aeronautics and Astronautics professor, told Business Insider.

Plane features made of plastic and composite materials such as carbon fiber and fiberglass need the most protection from the heat of the sun. Therefore parts such as the nose cone of the plane, where the aircraft radar lives, and the control surfaces, which are made of composite materials, are all usually painted white or light grey, he explained.

Concorde had to be painted with a special highly reflective white paint so it could withstand the heat generated from supersonic travel.

“The power was gained using an engine reheat, where fuel is pumped into the jet pipe and set alight to give extra thrust,” British Airways said. “Concorde reached 127°C at the nose and trailing edge, but special white paint helped reflect and radiate heat. Its reflectivity was 80 out of 100, compared to the rating of normal white paint of 45-50 out of 100.”

The Concorde was painted with a special highly reflective white paint Credit: getty

Damage control

The white colour of most aircraft makes it easier for any cracks, dents, oil spills and other faults to be identified and repaired swiftly.

Search and rescue

It depends where the crash occurs, but, should a plane go down, a white fuselage may well be easier to spot more from the air - another good reason for avoiding colour.

Reducing bird strikes

Aircraft visibility could be enhanced by white or brightly-coloured exteriors to potentially increase its detection and avoidance by birds, according to research, such as a US study published in the science journal Human-Wildlife Interactions in 2011.

The study looked at the correlation between bird strike rates among different airlines and aircraft colour schemes, assuming that “Darker aircraft colour schemes could potentially reduce the contrast between aircraft and the visual background [and] potentially reduce the ability of birds to detect aircraft in sufficient time to avoid a strike,” the report said.

Does this mean colourful aircraft are more risky to fly?

The Civil Aviation Authority says not. “There are no requirements from a safety point of view regarding aircraft paint schemes,” a spokesperson told Telegraph Travel.

Coloured features on planes also tend to fade and whiten over time due to oxidisation, Mr Hansman notes, following long-term sun exposure and other environmental factors.

Why bother painting planes at all?

Until just after the Second World War, most aircraft exteriors were left unpainted, or decorated with only the airline emblem, for economical reasons.

Even in modern times some airlines have avoided using paint on their aircraft. American Airlines, for one, has been known for its bare aluminium look. But, while this saves money, it leaves the aircraft exposed and unprotected, especially in harsh weather conditions.

Historically, some airlines have attempted to avoid using any paint on their aircraft, such as American Airlines Credit: Wikimedia Commons

“Those planes would start to tarnish over time so they had to spend time and money to polish them frequently. So, most airlines now use light coloured paint,” Mr Hansman said.

“Paint is more than aesthetic; it affects the weight of the aircraft and protects the integrity of the airframe,” says the US Federal Aviation Association (FAA).

“A properly painted aircraft is easier to clean and maintain because the exposed surfaces are more resistant to corrosion and dirt, and oil does not adhere as readily to the surface.”

The process of painting a plane

“Commercial plane skin panels arrive at Boeing covered with a temporary coating to protect the metal from damage or corrosion during the manufacturing and assembly processes,” said Bill Dill, a decorative paint manager at Boeing’s commercial aircraft factory in Everett, Washington.

The second layer is considered a polish, while the third is a more decorative layer, when the plane’s upper half, vertical stabiliser and rudder are fully painted, using colours if required.

The weight of the paint job differs according to whether two or three layers are used. “While the lighter weight of a polished plane saves fuel costs, the savings are more than offset by the higher cost of washing, polishing, and painting a polished fuselage throughout its service life,” says Boeing.

The maintenance cost of polished planes is said to cost £59,641 ($82,000) more per year than fully painted planes.