I couldn't use an air horn, unfortunately, as my dogs are sensitive to sudden, loud noise and would probably be bothered more by the horn than the oncoming dog would be.
I'm overprotective of my dogs. I have Border Collies, they're not built to fight other animals, but they're tenacious little dogs and won't back down if threatened. If a dog comes up to us and acts aggressively, my dogs will react and if it's a big strong dog, it's going to be a bad outcome for my gutsy crew. So if I see a dog coming towards us and posturing aggressively, I'm not going to be gentle and tell them to "shoo, shoo" or give up if stomping my feet at them doesn't work. I've found that a good whack to the head with the clip end of a lead is effective, especially if you have heavier hardware on your lead.
I'm overprotective of my dogs. I have Border Collies, they're not built to fight other animals, but they're tenacious little dogs and won't back down if threatened. If a dog comes up to us and acts aggressively, my dogs will react and if it's a big strong dog, it's going to be a bad outcome for my gutsy crew. So if I see a dog coming towards us and posturing aggressively, I'm not going to be gentle and tell them to "shoo, shoo" or give up if stomping my feet at them doesn't work. I've found that a good whack to the head with the clip end of a lead is effective, especially if you have heavier hardware on your lead.