Why don't you try taking your dogs breakfast and/or supper mixed with some five star treats in a plastic bag and ask him to sit and look at you and reward him for doing so. Dogs approaching each other head on is not a natural way for dogs if on their own they curve in and out on an approach. I would teach your dog to walk in serpentines and circles so the approach is less direct. You may also want to consider an easy walk harness or a gentle leader. My experience is that dogs that are reactive in this way are usually uncomfortable and need to be taught an alternative behavior where they can be successful. You can also teach your dog a watch or a look command.