Latin American plans to develop a low-cost trainer aircraft are moving forward but too slowly to raise hopes about the original aim of having the first of a new fleet of trainer aircraft in the air by 2015.

The joint trainer project is a long-delayed undertaking by the Union of South American Nations, often compared with the European Union but increasingly seen to be extending its role in defense and military coordination among members.

Several Unasur members -- Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay and Venezuela -- are also members of other regional organizations, including the Mercosur trade bloc and Andean Community of Nations.

In addition, Unasur's joint trainer project is seen by analysts as running counter to extensive defense and aviation development programs under way in Brazil.

Despite those apparent contradictions, Unasur is determined that member nations should have one type of locally manufactured aircraft that regional air forces can train on. The aim, says Unasur, is to move toward defense and security integration.

In April, Unasur appeared to advance the project with the announcement a Unasur-7 prototype was on track for completion next year. Official participants in the Latin American defense and security show in Rio de Janeiro offered scant details but previous reports in the Uruguayan news media indicated most of the work might be in progress in Uruguay rather than Brazil.

Five key Unasur member countries -- Argentina, Brazil, Chile, Columbia and Uruguay -- are also partners in a more advanced tactical transport plan being developed by Brazilian aviation giant Embraer.

Embraer's KC-390 tactical transport plane project has been securing international partners as part of a strategy to take on bigger rivals including Lockheed Martin. Embraer sees its KC-390 filling the gap to be left by a global phasing out of Lockheed Martin's C-130 Hercules. But it's far from clear how Embraer regards the launch of Unasur's joint trainer program.

Brazilian Neiva T-25 Universal is among trainers due to be phased out. The propeller-driven basic trainer and ground attack aircraft was manufactured by Industria Aeronautica Neiva in the 1960s as a Brazilian air force replacement for the T-6 Texan Fokker S-11 and S-12 then in use.

The problem is that delays in Unasur actually implementing the joint trainer program have encouraged other manufacturers to try to enter the market.

Unasur has been talking about the trainer development program but hasn't said who will design and build it. An April announcement by Unasur defense ministers left many of those questions unanswered but released instead a long list of specifications that officials said would be "good to have."

In November last year, Unasur's South American Defense Council agreed an "action plan" for developing the joint trainer aircraft. Uruguayan air force sources told Uruguay's El Pais newspaper they would be taking part in the development of a joint trainer aircraft.