flapping noise by hood/windshield?

Near where the hood meets the windshield, on both the left and right sideof my 01 Denali, there is a flapping noise as I increase in speed. There is a rubber flap/ cover type piece on both the left and right side but I have removed that and still hear the noise. I don't think it is a problem with my car per say - just annoying as heck when driving.

Any suggestions?

the black plastic piece that goes all the way across windshield is loose. get some clear caulking lift up just enough to put a bead under driver and pass side then press down lightly allow to sit overnight. Believe me it drove me crazy 2. No more noise

I don't know about the '01 Denali but the '01 Yukon XL has two black trim strips ( left and right sides ) running vertical on windshield. These will eventually start to flap with increased road speed. Open door, hold back door seal, take out the 4 screws on each and double stick tape the trim to the windshield or use silicone sealer. Replace screws. Stopped the noise for me.