Dushanbe International Airport (DYU) receives flights from Moscow, Istanbul, Dubai, and several other Central Asian capitals. Tajik Air and Somon Air are the national carriers; Turkish Airlines flies from Istanbul with decent connections from Europe. Flying in from Moscow tends to be cheaper than routing through the Gulf.
Overland entry is possible from Uzbekistan (Termez border crossing, then a long drive or train), Afghanistan (a border post at the Amu Darya bridge, manageable for adventurous travelers with the right paperwork), and Kyrgyzstan (via the Kara Myk pass, seasonal). Most travelers arrive by air.
From the airport, taxis to the city center take about 20 minutes. Agree on a price before getting in; the standard fare is low by Western standards. There are no scheduled bus services from the airport.