If you're not driving your own car, sharing a ride with someone, renting a car, or hitchhiking, there are usually three paid ways to travel from one place to another over long distances - bus, train, and plane.
In the United States, the Greyhound bus and Amtrak train companies as well as Delta, Virgin America, and Alaska airlines are some major forms of transportation.
Going by bus is usually the cheapest and most convenient overall but takes the longest, followed by the train, and taking a plane is the fastest but also the most expensive.