Mark Yanchak of Everett, Wash., was flying out of Sea-Tac International with his family Saturday, KIRO-TV, Seattle, reported.
Yanchak said his 3-year-old was being fussy as the plane prepared for takeoff.
"He was crying, being cranky," said Yanchak. "I started putting him in his seat. I put his seatbelt on. But he was being cranky, trying to be close to me, so he wasn't fully fastened yet."
Yanchak said his wife, who was sitting with the couple's other son and her mother in first class, came back to help settle the 3-year-old down and they eventually were able to get the boy to sit still.
But by then, the pilot was heading back to the gate and a representative for Alaska Airlines asked Yanchak and his 3-year-old son to get off the plane.
"They wouldn't tell us why," said Yanchak.
Alaska Airlines said it was a judgment call. The pilot and crew were concerned because the boy did not want to sit still or wear his seat belt.
The airline said the pilot preferred to deal with the issue on the ground rather than mid-flight.
Yanchak said the airline offered to book his family on another flight, but he said they have no desire to take any flight with the airline again.