Noise from dash?

Several times a year we drive to WVA from Cleveland Ohio to a casino. On the way down, no problem. About half way driving back on the turnpike, when we travel 70-75 mph, a whistle type noise comes from the dash. When we stay under 70, no noise. ??

Was the windshield ever replaced?
If so, it could be an air leak at the base of the windshield that is making the noise.
This is actually not that uncommon when a windshield is not sealed properly.

thank you for your quick reply. No, the windshield has never been replaced. I am actually guessing that the whistle sound is coming from the dash, because that what it sounds like to me. I don’t understand why driving down to Wva, no noise, just on the way back going over a certain speed – very strange!