The A400M, a long-awaited new military transport plane, will take to the skies at the upcoming Paris Air Show before finally setting out to conquer markets worldwide after a four-year delay.

Built by Airbus Military, the giant plane can carry helicopters, people or armoured vehicles weighing up to 37 tonnes over 3,300 kilometres (2,050 miles) and is able to land directly in combat areas on rough terrain, even on sand.

"It allows operators to deliver strategic sized loads (such as armoured vehicles) directly to the point of need on remote and austere landing strips," says Gareth Jennings of defence and security analysis firm IHS Jane's.

The plane is also equipped to provide in-flight refuelling for two planes or helicopters.

The main two other transport aircraft on offer today are built by US firms. Lockheed Martin's C-130 Hercules has a smaller payload and Boeing's C-17 Globemaster can only land in big airports.

Airbus Military hopes to sell 400 of the aircraft -- its propellers measuring more than five metres (16 feet) in diameter -- over the next 30 years, on top of the 174 already ordered in Europe and in Malaysia.

France's defence ministry will be the first to take delivery "in the next few weeks" of the plane, which is assembled in Spain as part of the biggest European programme on collaborative procurement.

"We are targeting the Gulf and Asia-Pacific areas, where many countries are renewing their fleet," said Domingo Urena-Raso, the head of this subsidiary of European aerospace and defence group EADS.

"But the best marketing will be undertaken by airforces that will demonstrate the capabilities of the plane during their operations."

He said he was banking on French, British and Turkish air forces "to promote the new aircraft in the closed club of air forces."

The target to sell 400 planes is ambitious, as Lockheed-Martin has only exported 218 of its C-130 aircraft and Boeing has sold 145 of its C-17s abroad.

But Jennings says it "is not an unrealistic target" as the A400M occupies a niche position.

"The US is very aggressive in marketing its products, but in this case the US has no comparable product to market," he said.

"The Russians and Ukrainians are developing the An-70, which is broadly similar in size and capability as the A400M, but this aircraft has not yet been built, and its 'on/off' history makes it doubtful that it ever will be."

Designed at the request of European NATO states after the first Gulf War in 1991, which highlighted the need for such a plane, the A400M has already been ordered by seven European countries including Germany, Spain and Belgium.

The French army was due to take delivery of the first plane before the Paris Air Show, which kicks off on Monday, but this was postponed until the summer in another delay that has plagued the ambitious programme.

All in all, the A400M is more than four years behind schedule, due to problems such as the development of new turboprop engines -- which drive the plane's propellers -- by a consortium of four firms.

The programme has gone over its initial budget by some 6.2 billion euros ($8.3 billion), or by around 10 percent. But Airbus maintains that all technical problems have now been resolved.