No, he hasn't denied the moon landing as far as I know. I haven't heard the episodes you're referring to, but he's had other guests like Neil DeGrasse Tyson and

No, he hasn't denied the moon landing as far as I know. I haven't heard the episodes you're referring to, but he's had other guests like Neil DeGrasse Tyson and Elon Musk who have discussed space travel and he's never expressed any skepticism about it.