An Idaho man accused of slapping a child and using a racial slur on an airplane pleaded not guilty to federal assault charges in Atlanta on Wednesday, his lawyer said.

Joe Rickey Hundley of Hayden, Idaho, is accused of striking a 19-month-old boy in the face on board a Delta Air Lines flight on February 8, according to documents filed in U.S. District Court in Atlanta.

The boy's mother, who was seated with her son, said in interviews that the child was crying as the plane from Minneapolis descended into Atlanta.

An attorney for Hundley, 60, said he used a racial slur when the child started crying because of ear pressure, but she denied that Hundley struck the boy.

The baby is Black and his adoptive mother, Jessica Bennett of Minneapolis, is White. Hundley also is White.