Most everything about this neat little movie has been said by previous posters, except this.
The motivation for making it was, of all things, the US State Department! The US was deeply involved in fighting World War Two. At this point in time the average American knew almost NOTHING about South America, and the Nazi government was busy making business and political connections there, especially in Paraguay... there, transplanted Germans were a well established colony. They were aiding Hitler's war effort with the operation of industrial concerns, as well as providing espionage support.
South America promised to become a new battlefront if German successes and infiltration continued. The region produced vital strategic raw materials, key among them rubber.
Our strongest ally in the region was Brazil. The US Navy had a number of installations there, both sea and air. The Brazilian Navy worked closely with US forces in hunting U-boats in the Atlantic narrows; a number of US Navy vessels were transferred to them. American air bases (the largest of which was at Recife) provides home base for American aircraft, both fixed wing and lighter than air blimps, to provide air support coverage to trans Atlantic convoy operations.
The State department felt it would be a good idea to familiarize Americans with the land, people, and way of life of South America, and called on Disney to produce THE THREE CABALLEROS. The movie was, first and foremost, a TEACHING TOOL for both military forces and the general public during a global war.
BTW... I love the crazy little bird too! HE'S the best part of the film!
There are two other Disney films made for the Government that I'd LOVE to find copies of.
One is VICTORY THROUGH AIR POWER, another WW2 product.
The other is one that I saw back in Basic Training in the 1970s. Believe it or not, the Walt Disney studios produced a military training film on the prevention of VENEREAL DISEASE!!! The unfortunate Lady dispensing said commodity bore a VERY striking resemblance to Snow White!
Because of that film I can never view SNOW WHITE in quite the same way ever again!
