While inarguably the company's highest-profile defense project of recent memory, the new KC-76 aerial refueling tanker that Boeing (NYSE:BA) is building for the U.S. Air Force isn't the only tanker Boeing's got up its sleeve.

On Tuesday, Boeing announced that it's teaming up with Brazilian  planemaker Embraer (NYSE:ERJ) to help market the latter's KC-390 multimission mobility and aerial refueling aircraft. Embraer will build the airplane; the agreement calls on Boeing to take the lead in KC-390 sales, sustainment and training opportunities in the U.S., U.K. and select Middle East markets.

The KC-390 is said to be the biggest airplane ever built in Brazil, capable of carrying up to 80 passengers, 23.6 tons of cargo. Commenting on the announcement, Embraer Defense and Security CEO Luiz Carlos Aguiar called the KC-390 "an extremely capable aircraft that continues to attract interest by several nations."

The companies initially estimate the total global market for the KC-390 is 700 aircraft.