An email from federal prosecutors did not say what charge Joe Rickey Hundley will plead guilty to during a Wednesday afternoon hearing. He faces a misdemeanor simple assault charge.
His trial had been set to begin Thursday in federal court in Atlanta.
Authorities say Hundley used a racial slur to refer to the 19-month-old boy and then hit him under the right eye as the flight from Minneapolis began its descent to the Atlanta airport in February.
Hundley lived in Idaho at the time but has since moved to North Carolina.