I have Honda Fit 2016, only 2500 miles on it, it makes on/off humming sound only when its on the highway over 60mph, it doesn't matter if you turn or change lane, no vibration, its not loud, and its less noticeable when deriving on new soft pavement, again is on/off humming, not constant, and there's absolutely no sound below 60mph speed. I thought about the tire tread sound, but I feel any regular tread surf when I move my palm hand on the surface, I thought about bearing wheels, but bearing wheels sound is a constant sound not on off and it can be heard when car go over 35mph, I did grasp the tires at the 12/6 position and tried to rock the tire and wheel in and out, found no play.
My car has 2500 miles.
My car has an automatic transmission.
Since the car is new and under warranty, the Honda dealer should be able to help you out with this. If it’s a noise that’s more obvious over rough or course pavement, and less so on smooth pavement, it can possibly be a loose trim panel either inside or outside/underneath the vehicle, loose exhaust system, etc. Make sure anything inside the vehicle - spare tire/jack, etc. are all properly secured. It’s possible that there is something somewhere that is just loose enough that it takes a certain "frequency" like speed or coarseness of pavement to make the noise obvious. If you would rather have an independent technician inspect the sound, a technician from YourMechanic would be able to pinpoint the noise and perform any needed repairs at your home or office.