Leopold Stokowski, a popular conductor of the day, was known for his long and often unkempt mane of hair. He is the inspiration for the "conductor" here. This character popped up quite a bit in cartoons from the era, such as "Fantasia" (1940) and "Long-Haired Hare" (1949).
Concerto com Rebites (1941)'s background was a musical composition of Franz Liszt's Second Hungarian Rhapsody that was in two later shorts, Bugs Bunny's Concerto Sem Dó (1946) and Metro-Goldwyn-Mayer's Concerto para Gato e Piano (1947) that won an Academy Award.
Construction workers resembling Porky Pig and Droopy Dog are among the varied workers shown.
A sidelong wink at Disney's "Fantasia" (1940).
This short features no dialogue.