The dozen-odd robbers fired gunshots and tear gas as they tried to flee after the heist late Friday at the airport in the southern city of Juliaca.
Part of the loot -- 30 kilograms of gold and Peruvian soles worth USD 300,000 -- were recovered and six suspected robbers were arrested.
The thieves burst onto the runway in two vehicles and robbed three armored cars that were delivering the gold and money to a plane waiting to take off for Lima.
As the gang opened fire in their flight, passengers of two planes on the runway had to duck for cover.
Police director general Vicente Romero said the gang was very well organized.
The six arrested suspects face life in prison.
The gang had planned to flee to neighboring Bolivia. One of the detainees is Bolivian.
Peru is enduring an unprecedented crime wave. Crimes involving hired killers and extortion have become everyday occurrences.
A poll released in July found that 76 percent of Peruvians say they do not feel safe in their country due to rampant crime.
