Staff members began arguing with the Schears because they wanted their 2-year-old son to be allowed to fly in an individual seat while fastened into a car seat, according to the video.

…The employees can be heard telling Schear that both Delta’s guidelines and Federal Aviation Administration rules stipulate that a 2-year-old child must fly while seated on their parent’s laps, but rules posted on each agency’s website appear to contradict that.

…“How did we get through security with two kids, two car seats, go all the way through your gateway, and through the gate and then they come down and say that we have to get off this plane?” he asks.

An employee insists they were simply trying to help the family, prompting another irritated response from Brian Schear.

“Trying to help us would have been not overselling the flight and not trying to get him out of that seat, that I paid for,” he said.

Orange County family says they were kicked off Delta flight after argument over child’s seat – LA Times

Lesson here? Do not fly airlines based in the US!!!!!