In the book bud not buddy What were the flyers in bud's suitcase advertising?

In "Bud, Not Buddy" by Christopher Paul Curtis, the flyers in Bud's suitcase were advertising a series of jazz performances by a band led by the fictional musician H.E. Calloway. These flyers serve as a clue to Bud's quest to find his father, as he believes that Calloway might be connected to his family. The flyers reflect the importance of music in the story and Bud's determination to uncover his roots.