Most states in the US have at least one international airport and all major cities usually have more than one international airport serving a large number of airlines with connections worldwide. There are also many domestic airlines operating regular flights throughout the country across all states. Discounted fares can usually be purchased easily due to tough competition between airlines making domestic travel relatively inexpensive. The distance when travelling by air from East to West is no more than 5 hours and 2 hours from North to South.
In many states it is possible to travel by water along the many rivers, lakes and inland waterways.
Travel by rail is generally not considered the best form of transportation in the US for long distance travel. Fares can be relatively expensive and train times can be irregular. The main rail operator is Amtrak which serves a rail network spanning 45 states. Other smaller operators also provide inner-city rail connections and rail travel to more rural areas in most states.
Public transportation is generally good in most states. Regular bus services operate in all major cities and are fairly inexpensive. Most major cities including New York, Washington, Boston, Chicago and San Francisco also have comprehensive underground rail systems and trams and trolleybuses also operate in some cities.
Coach services also operate between major cities and states.
Taxis are widely accessible in most major cities. Fares vary from state to state and it is important to include a tip with the fare in line with the tipping culture in the US.
Travelling by car is by far the most common mode of transport used throughout the US. The US has a very efficient system of roads and highways making it easy to travel between cities and states and in more rural areas. A valid national driving licence is sufficient to drive in the US for one year (although it is recommended that you acquire an International Driving Permit). Following which you are required to obtain a US driving licence which will be valid for the state in which you hold residency.