NEW YORK (Reuters) - The worldwide commercial aviation industry will need an extra 255,000 pilots by 2027 to sustain its rapid growth and is not moving fast enough to fill the positions, according to a 10-year forecast published by training company CAE Inc CAE.TO.

FILE PHOTO: An Alitalia pilot holds his cap at Fiumicino international airport in Rome September 24, 2008. REUTERS/Max Rossi

More than half of the required pilots have not yet begun training, the report adds, storing up potential problems as the industry braces for an increase in passenger air traffic that is expected to double the size of the commercial air transport industry in the next 20 years.

“Rapid fleet expansion and high pilot retirement rates create a further need to develop 180,000 first officers into new airline captains, more than in any previous decade,” said the report by CAE, which trains pilots for airlines around the world.

“The shortage of pilots is a problem today. There’s demand today, so people need to start building a strategy with us or other professional academies to be able to build that pipeline,” Nick Leontidis, CAE’s Group President for civil aviation training solutions told journalists at the Paris Airshow on Tuesday.

Rival L3 LLL.N also operates pilot training academies.

To meet demand, Leontidis said CAE would seek to grow its own training academy business, rather than make acquisitions.

Pilot unions in the United States have said low wages and limited benefits for entry-level positions are deterring a new generation of potential aviators from pursuing the career.

In the United States, training requirements also are a hurdle for many would-be pilots.

The United States is the only country to require co-pilots to have at least 1,500 flight hours unless they have experience flying planes in the military or are graduates of certain specialized programs.

According to the U.N.’s aviation agency, which sets global standards typically adopted by regulators from its 191-member countries, it takes a minimum of about 250 hours to obtain a commercial pilot license for work as a co-pilot.

By contrast, 1,500 hours is the minimum required to become a captain under norms set by the International Civil Aviation Organization (ICAO), the U.N. agency that supports the development of global aviation.

While the U.S. Federal Aviation Administration previously had followed ICAO norms, the 1,500-hour requirement for co-pilots was imposed following the crash of Colgan Air Flight 3407, a regional jet, in 2009, that killed 50 people.

The 1,500-hour mandate is supported by pilots’ unions as a way to improve air safety. However, regional airlines and some aviation experts say the tougher standard does not make flying any safer and has exacerbated the pilot shortage by making the training process longer and more costly.