Internal flights are possible on Turkmenistan Airlines which flies daily between Ashgabat, Mary, Turkmenbashi, Dashoguz and a couple other destinations. Flights are subsidised, and due to fuel costs, extremely cheap. Prices are around $5 US for a flight from Ashgabat to Mary or Dashoguz. Turkmenistan Airlines operates with a new fleet of Boeing 717s, purchased in 2001. Be aware that you might not be able to photograph freely in and around the airport, though this is not unheard of elsewhere.
It is possible to travel by train between some of the major cities in Turkmenistan, but journeys are slow up to 16 hours from Ashgabat to Turkmenbashi - so unless you have a specific interest, plane travel is the best way to get around the country.
Rail service in Turkmenistan is provided by Turkmendemiryollari Turkmenistan Zeleznice, Ashgabat, phone 3632 255545, fax 3632 473858. On the principal trains they offer soft and hard accommodation with sleeping and dining cars. Tourist using rail services in Turkmenistan must expect to pay higher charges than local people and to pay tickets in foreign currency. Turkmendemiryollari Turkmenistan Zeleznice runs trains from Ashgabat to Turkmenbashi and via Mary to Turkmenabat and return.
At least in Ashgabat, like in much of the former Soviet Union, "taxis" are mostly unofficial - and can be hailed by flagging down a car by the roadside. Haggle, and agree on the destination and price in advance - knowledge of Russian will definitely come in handy at this point.
The usual sensible precautions apply here. If your instincts suggest that something might be not quite right, then it's best to go with your instincts.
Roadblocks are in place throughout the country, so this method is really best used only within city limits unless you are specifically looking for trouble.
Drive on the right. Minimum age: 17. International permit required. Speed limit: 60 km/h in urban areas, 90 to 120 km/h on highways.