I always liked the idea that the Jetsons and Flintstones actually existed at the same time period. Flintstones being poor, have to make due with dinosaur appliances that speak. Smoking Winston brand cigarettes, we know the Flintstones must take place after the founding of the company, and the creation of American broadcast television. Everything makes slightly more sense as really poor people, living on earth, in the Jetsons future. I mean, Occam's razor dictates that when the Flintstones met the Jetsons, it's more likely that whoever said they travelled on time was wrong. The Smurfs did a similar episode where they gave stupid smurf a potion and pretended he was on a space ship to mars, so when he wakes up, he thinks he's o. Mars