The spectacular heist, which took place late Sunday, was completed in a matter of minutes, and authorities have yet to arrest a suspect.
The crooks entered Viracopos International Airport's freight terminal using a pickup on which they had "placed stickers mimicking the runway security company's logo," federal police said in a statement.
Germany-based Lufthansa's plane had been traveling from Guarulhos airport in Sao Paulo and was making a stop at Viracopos Brazil's biggest freight terminal with Zurich as its final destination.
The stolen money had been held under the auspices of secure transport provider Brinks, according to the Folha de Sao Paulo newspaper.
The daily said five men had threatened security agents on the runway before taking off with the cargo, in barely six minutes.
Cargo theft is on the rise in Brazil, where most targets are semi-trucks, especially those serving Rio de Janeiro.
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