It's an idea to have him thoroughly checked by your vets for any possible medical problems which could be causing his aggression before embalking on any rehabilitation programme. It's not unknown for some dogs to be found to have a chemical imbalance in the brain or other issues and medication has helped immensely. There might be nothing wrong but it's best to rule that out as wasting loads of time and money training when the problem is medical is not a good idea for anyone.

When it comes to noises, the best thing would be to gradually desensitize him to various sounds. Starting off with him further away so that they aren't as loud and gradually moving closer with lots of positive reinforcement without taking him over his threshold. Here is a link to a youtube channel containing videos made by it's creator about how to train dogs in various things. There's a few vids on barking and reacting to things like noises etc...Emily uses clicker training and it's all positive reinforcement.
http://www.youtube.com/profile?user=kikopup#g/u

If aggression is not caused by a medical problem, it generally stems from fear or anxiety of something and is learned as a means of the dog coping with or preventing situations it does not like.