I would suggest two dates of significance to Brazilian Air Force in WW II. Being the sole South American Air Force to enter combat in Europe it´s worth mentioning.
1 - December 18 (1943) First Fighter Aviation Group of Brazilian Air Force is created.
2 - April 22 (1945) Fighter Aviation Day: On this date the 1ºGAvCa (First Fighter Aviation Group) realised 44 combat missions in a single day.
The complete history can be read here:
http://www.rudnei.cunha.nom.br/FAB/en/index.html
Enter History, then At Wat.