Dog Fears and Phobias
Nervous fearful behaviour may lead to aggressive behaviour in a dog. Aggressive behaviour can be displayed in an attempt to repel the subject that it fears. However aggression does not always accompany nervous behaviours, as the dog may simply run away ears down, tail between its legs and doing its utmost to avoid the source of fear.
A dog can react in an irrational manner when it is experiencing extreme fear, so caution should be exercised in terms of personal safety.
I have seen and helped resolve fear related behaviour towards hot air balloons, cars and members of the family to name but a few.
Dogs can develop quite irrational fears at times towards virtually any object, so gradually building the dog's confidence in the area of concern is essential.