When Barbara is taking food from the refrigerator to take for the picnic, she removes a whole pie with a white meringue or cream topping. As she finishes packing the food, on top of the boxed food she places a half eaten chocolate pie.
During the scene where people are up on their rooftops as they watch TV and see the first manned landing on the moon, the moon is shown above as a full moon. In actuality, the moon was still in its first quarter and looked like a crescent slightly less than a half-moon.
In the beginning of the film, after it has jumped to 1969, the glimpse of the Manhattan skyline shows the skyline as it looked in 1993 (the Citicorp building built in 1978 is shown), and not as it would in 1969.