Here is a list of relevant airports:

Antalya - (St Paul Trail and Lycian Way). Antalya has a modern airport handling 10 million passengers per year, only 15km E of the city. From the domestic terminal there are:

• city buses to the bus garage every half-hour; you can change to the tramway to access the city centre.
• Havas buses to Antalya centre several times per day.
• Taxis cost about 35 MTL/15 Euros to the town centre and a bit more to the main bus garage.
  

Dalaman - (Lycian Way). Dalaman has a modern international airport handling several million passengers per year. From the airport, Dalaman bus station and town is 3-4 km taxi ride. Frequent buses go from the bus station to Fethiye and Antalya up to 12 midnight.

Erzurum - (Kaçkar South side) Erzurum airport (15km W of the city) is mainly a domestic airport and is closed at night. Buses run to the bus station and town centre.

Trabzon - (Kaçkar North side) Trabzon airport, 5km E of the city, has domestic and international terminals. Coast road buses pass the airport gate.

Airlines:

Turkish airlines/Anadolu Jet (THY): All internal airports to Istanbul/Ankara; many external destinations www.turkishairlines.com

Pegasus Airlines: Istanbul, Antalya - European and Russian destinations; Trabzon - Europe and Georgia. www.flypgs.com

Sun Express: Germany, Holland, Belgium, Switzerland, Austria (all year around) to Antalya, Bodrum, Istanbul. www.sunexpress.de

Air Berlin: Germany to Antalya. www.airberlin.com

Onur Air: Istanbul to Trabzon and Erzurum; UK, Germany, France, Denmark, to Antalya and Dalaman; Spain to Istanbul. www.onurair.com.tr

Sky Airlines: German airports to Antalya. www.germanskyairlines.com. Istanbul, Ankara to Trabzon, Dalaman, Antalya; www.skyairlines.net/tr

Atlas Jet: Istanbul to some Turkish and eastern destinations www.atlasjet.com

Thomas Cook (chartered): Many UK destinations to various Turkish airports. www.thomascook.com

Bus services: The overnight buses are one of the wonders of Turkey –they run on time, are clean and well serviced and are comparatively cheap. www.bilet.net/otobus is a good starting point; they also have train information.

Dolmuşes
Minibuses called dolmuşes run in towns and between villages. Usually they run at set times, starting early in the morning and finishing at about 6 or 7 pm (later in towns).

[updated, december 2012]