Hi, he needs to know that hitting is unacceptable. When he becomes aggressive like tell him we do not hit and try to have him sit in a corner and tell him he is in time out or he needs time to control his anger. If you do not do anything this behavior will continue, you would also have problems in school with him hitting other children.
Most pediatrians encourage the parents to stop giving the bottle at 1 yrs old. Try slowly taking it away. Replace the mill with a little water. Then take the bottle away completely. He will scream he will fight you but remeber you are in control. Just let him know that you are here for him and let him "scream" it out. He will soon know that he has bo leeway. Kids test us all the time and they know what they can do to get what they want out of us. My two year old starts to say "im scared" everytime i put her to bed so that she can stay awake lol. At first I thought she was really scared then I realized she got to me so I would comfort her and have her go back to bed.
Also try talking to your pediatricians they always know more ways to help. And don't worry my 2 year old went through that phase for a couple months but now she knows that we dont hit.