The Gulf state's civil aviation authority on Saturday announced the first of the three phases for the construction of New Doha International Airport would begin this year and be completed by late 2008.
"The airport will be one of the biggest in the world with an annual capacity of 50 million passengers in Qatar when it is finished around 2015," Qatar's head of civil aviation Abd al-Aziz al-Nuaimi said.
The first phase would cost $2.5 billion.
Bechtel's engineering, project and construction management contract includes the design, project management and construction management of the new facilities, covering a site of approximately 8.5 square miles, four kilometres east of the existing airport.
"The new airport will position Doha and Qatar as a leading regional aviation hub for the next 50 years," Bechtel's Senior Vice-President James Van Hoften said.
The new airport would need reclamation of a large area of land from the sea, the construction of two parallel runways, a passenger terminal with 25,000 square metres of retail space, a special royal terminal, a free trade zone and three hotels.
"The airport will also be pivotal to the continued significant growth of Qatar Airways as a global airline," Qatar Airways chief executive officer Akbar al-Bakr said.
A statement from the civil aviation authority also said the upcoming airport would be the world's first airport to be designed specifically for the Airbus A380-800, the world's largest passenger aircraft.