If I am flying from Montreal to Charlotte at 09:21 then leaving Charlotte at 11:27 to Aruba, will I have to still go through customs again or can I just connect to my next flight

I think u just connect

We went thru the US costum and do the process again thru check point where they scan your personal items. We also dropped the luggages near the custom for the next flight. We were flying from Spain to Austin connecting in Charlotte

You need to go thru US costume and then do the process thru checkpoint. Is because you came out over sea or boarder you need to do the process.

If you do not exit the airport but remain in the terminal, you will not have to go thru security again.

You just connect