Several Swedish business leaders also joined the royal party.
Swedish company Saab is competing in the Brazilian jet tender with its Gripen NG mono-motor fighter.
Although the plane is seen to be favored by the Brazilian air force, Brazilian President Luiz Inacio Lula da Silva and his defense minister, Nelson Jobim, have repeatedly said they prefer the more powerful but more expensive Rafale jet by France’s Dassault company.
The third aircraft in the running, the F/A-18 Super Hornet by US group Boeing, is seen as an outside contender only because of doubts that Brazil would obtain the total technology transfer it is seeking as part of the deal.
The winning company will supply 36 fighter jets to Brazil, for an initial value of between $4 billion and $10 billion, with the possibility of many more fighters being added later on.
A decision is expected within the next two weeks.
Saab is going all-out to bolster its chances, taking out full-page colour advertisements in the Brazilian press and multiplying visits by top Swedish officials.
The Swedish king and queen were to dine with Lula late Tuesday.
Wednesday, they were to visit Brazil’s supreme court and congress, and meet Brazilian indigenous leaders, according to the Swedish embassy.
On Thursday, the couple was to attend a conference in Sao Paulo arranged by that city’s powerful industrial employers’ federation.
On Friday, the king and queen were to drop in on the factory of Brazilian aircraft manufacturer Embraer on the outskirts of Sao Paulo.
Queen Silvia, though born in Germany, is of Brazilian descent through her mother and spent 10 years of her childhood growing up in Brazil.