Sulawesi has  6 (six) provinces and all these provinces has one major airport served by regular flights connecting various towns and cities in Indonesia. But only two provinces have international airport. They are Makassar in the South Sulawesi Province and Manado in the North Sulawesi. These two airports are now the gateway to the island.

Makassar now has regular flights connecting the town with Kuala Lumpur in Malaysia flewn by AirAsia 4 (four) times aweek. Whilst Manado international flights served by Silk Air ( 3 times a week) and AirAisia (also 3 times a week). Here are the details

Makassar: the major airport on the island. It is a hub and distributing point of flights in Eastern Indonesia

• International flights: flewn by AirAsia 4 times a week connecting Makassar with Kuala Lumpur / Malaysia
  
• Domestik flight: flewn by various airlines run on daily basis connecting Makassar with Denpasar/Bali, Jakarta, Surabaya, Jogyakarta, Bandung, Medan, Manado, Ambon, Jayapura etc. The airlines flying to and from Makassar: Garuda Indonesia, Merpati airlines, Lion Air, Sriwijaya Air, Mandala Airlines, Celebes Air, etc
  

Manado: the second lagerst airport on the island

• Internationa flights: Flewn by AirAsia (3 times a week) connecting Manado  with Kuala Lumpur/Malaysia and SilkAir (3 times a week) connecting Manado with Singapore.
• Domestic flights: flewn by various airlines on daily basis connecting Manado with Makassar, Jakarta, Denpasar/Bali, Surabaya and Sorong. Less domestic airlines flying to Manado in comparisson to Makassar

To get to Sulawesi it is also accessible by water transports. PELNI Lines - the government owned passengers ships run regular routes cennectiong various towns and cities in the country including the island of Sulawesi.