(Adds details of airport concessions, context)
SAO PAULO, Nov 22 (Reuters) - Brazil opened two of its busiest airports to private investors on Friday, awarding $9 billion worth of concessions in Rio de Janeiro and Belo Horizonte in a push to overhaul the country's crowded terminals.
Brazilian conglomerate Odebrecht and Singapore's Changi Airport Group will have two years to expand Rio's Galeão airport before the city hosts the 2016 Olympics, sprucing up an underwhelming international gateway to Brazil's postcard city.
Local contractors and foreign airport operators won the two concessions for a combined 20.8 billion reais ($9 billion), paying a premium of more than 250 percent over minimum bids.
Brazil's CCR SA and the operators of airports in Zurich and Munich edged out builder Queiroz Galvao and Spain's Ferrovial for rights to Confins airport in Belo Horizonte in a bidding war that drove up its offer 30 percent.
Airports have been the most appealing part of President Dilma Rousseff's plan to privatize some 200 billion reais of infrastructure projects, breathing new life into Brazil's clogged roads and ports.
The latest concessions follow a hotly contested auction in February 2012 that awarded rights to major airports in Sao Paulo and Brasilia for 24.5 billion reais - more than four times the minimum bids.
Companies are clamoring for part of an air travel market that has doubled in less than a decade as some 40 million Brazilians entered the middle class and took to the skies.
Three years ago, 14 of Brazil's 20 biggest airports were running far in excess of capacity, according to data from state airport operator Infraero, which retains a 49 percent stake in the privatized airports.
Both airports in Friday's auction are pushing capacity, according to Brazil's civil aviation authority ANAC.
Odebrecht and Changi, which paid 19 billion reais for rights to Rio's Galeão airport, plan about 5.7 billion reais of additional investments over the next 25 years. They will add 26 new gates and expand cargo storage at the airport, which is officially named after Antonio Carlos Jobim, the late bossa nova musician and composer.
CCR and partners Flughafen Zuerich AG and Flughafen Munchen will add a new terminal and landing strip at Confins airport on the outskirts Belo Horizonte - Brazil's third-biggest metropolitan area, with over 5 million residents.
Visitors to both host cities for the 2014 World Cup will have to rely on state-run construction at the airports in recent years aimed at accommodating the crush of foreign fans.
($1 = 2.31 Brazilian reais) (Writing and additional reporting by Brad Haynes; Editing by Bernadette Baum)