My father was 19 years old and living in Newark when the World Fair was held in NYC. I remember him mentioning it but don’t know if he visited the Fair. Do you know what the grounds are used for today?
If you mean the ‘64 Fair, I’m the same age as your Dad.
http://www.nycgovparks.org/sub_your_park/vt_flushing_meadows/vt_flushing_meadows_park.html
It had fallen into disrepair for the most part to the best of my knowledge. From the site linked above, it seems like it has made a come-back. FReeper ari-freedom would prolly be better able to give you an up-to-date account.