The term "auto-mobiles" refers to vehicles that are designed for transportation, but not all vehicles fall under this category. Some antonyms for automobiles include bicycles, motorcycles, and scooters, which are powered by human energy or by small engines. Another antonym for automobiles is trains, which are typically powered by locomotives and travel along a fixed track. Boats and ships are also antonyms for automobiles since they travel on water and are powered by engines or sails. Airplanes and helicopters are other antonyms for automobiles, as they are designed to fly and transport people or cargo through the air. In summary, there are various antonyms for "automobiles," depending on the mode of transportation and the source of power.