Hello, I seem to have a problem with my 15 month old male labrador, his name is Skippy.

It all started 3 months ago, we used to walk him and then allow him to play with a pack of young dogs on a field close to our home. One day
an older but well trained Rottweiler came with us and Skippy just snapped at him, he started to bark and even attacked the other dog. The rottweiller responded. We managed to break them off.

After that we began to think Skippy might be the dominant one in the family, and was the dominant one in the pack before the other one came.  We started some training, just us and him. He doesn't walk in front of us anymore, he waits for us to get out of the house first, so we made some progress.

Even so, whenever he sees that rottweiller he goes crazy. Now it starts with other dogs, male ones only, and some little dogs(in size I mean). He's not affraid or smth, he just barks and attacks.

On the other hand he seems to be affraind of many things, large objects, loud sounds. He didn't bark at people before but for the past months when he sees a bicycle, a horse, someone with anything in his hand like a stick or something he lays down and then just barks. I don't think he would ever attack a person but he does bark, and while some people understand, others don't. He also barks in the same way at kids and with a labrador kids tend to just come and pet him. Sometimes he is ok with that but other times, he goes crazy and I just feel embarrassed with him.

Do you believe this can be solved only through expert training (I thought about it but don't have the time right now), or can just my training pay off after some time? Also any other advice on how to train him would be usefull.
Thank you.