On my 2014 hybrid titanium, no sunroof, I am hearing a drumming type of noise, similar to a helicopter blade noise, from the interior of the car. It sounds like air turbulence and is almost deafening. I can only hear it when one or both rear windows are down and driving on the highway above 45 mph. If I put the front windows down while the noise is happening, the noise goes away. It happens on the highway when the engine is running or on ev mode. There is no noise if only the front windows are down.
It really sounds like an aerodynamic anomaly.
The day I tried it, it was somewhat windy and cold, so I don't know if that has anything to do with it.
I normally do not drive with the windows down on the highway, so I am not really going to worry about it. Otherwise the car has been perfect.
I am asking if anyone else can do the same test and post what you find.