Thailand is advertising to be the hub of South East Asia and flying within Thailand is easy & cheap. So where to you start? First of all Bangkok has 2 airports. Don Muang Airport (DMK) and Suvarnabhumi Airport (BKK) and they are about 28 km from each other. But there is an shuttle bus between the 2 airports, that takes about 1 hour.
Don Muang Airport is the old military airport and is mostly used for domestic flights but also has and increasing number of international flights. Mostly operated by budget-airlines. This airport is located on the north side of Bangkok. According to the AOT the following airlines are flying from Don Muang Airport : Air Asia, Nok Air, Thai Lion Air, Mal Indo Air, Scoot Air, Tiger Air, V Air, Thai Smile, Siam Air, Orient Air, Sabaidee Air and Maldivian Air. Although I think some airlines are not flying at all anymore and some airlines are only flying international.
Suvarnabhumi Airport is the new airport and is mostly used for international flights but also has some domestic flights. This airport is located on the east side of Bangkok. From Suvarnabhumi Airport there is the Airport Link that connects to Bangkok downtown.
So what airlines are flying domestic in Thailand?
Information is from 20 November 2018 and can change every day.Thai Airways (Thai Airways)
Flies only from Suvarnabhumi airport and flies to Chiang Mai, Chiang Rai, Khon Kaen, Koh Samui, Krabi, Phuket, Hat Yai, Lampang, Sukhothai, Surat Thani, Trat, Ubon Ratchathani and Udon Thani. International they fly to almost the all world.
Air Asia (Thai Air Asia)
Flies only from Don Muang airport, but both international and domestic. And flies to Buriram, Chiang Mai, Chiang Rai, Nan, Hat Yai, Khon Kaen, Loei, Krabi, Nakhon Phanom, Nakhon Si Tammarat, Sakhon Nakhon, Trat, Udon Thani, Ubon Ratchathani. International they fly to China, Myanmar, Indonesia, Brunei, Japan, India, Taiwan, Singapore, Cambodia, Macao, Korea, USA, Vietnam, Australia, Hong Kong, Vietnam, Laos, Nepal and some more countries.
Nok Air (Nok Air)
Flies only from Don Muang airport, but both international and domestic. And flies to Buriram, Chiang Mai, Chiang Rai, Chumpon, Hat Yai, Khon Kaen, Krabi, Lampang, Loei, Mae Sot, Nakhon Phanom, Nakhon Si Tammarat, Nan, Phitsanulok, Phrae, Phuket, Ranong, Roi Et, Sakhon Nakhon, Surat Thani, Trang, Ubon Ratchathani and Udon Thani. International they fly to Australia, China, Japan, Korea, Laos, Myanmar, Singapore, Taiwan and Vietnam.
Thai Smile Airways (Thai Smile)
Flies only from Suvarnabhumi airport, but both international and domestic. And flies to Chiang Mai, Chiang Rai, Hat Yai, Phuket, Khon Kaen, Ubon Ratchathani, Udon Thani, Surat Thani, Narathiwat and Krabi. International they fly to Bangladesh, Cambodia, China, India, Laos, Myanmar and Malaysia.
Lion Air (Thai Lion Air)
Flies only from Don Muang airport, but both international and domestic. And flies to Chiang Mai, Chiang Rai, Hat Yai, Khon Kaen, Krabi, Nakhon Si Tammarat, Phuket, Phitsanulok, Surat Thani, Trang, Ubon Ratchathani and Udon Thani. International they fly to Australia, Bangladesh, China, Hong Kong, India, Indonesia, Malaysia, Myanmar, Nepal, Pakistan, Singapore, Sri Lanka, Taiwan and Vietnam.
Bangkok Airway (Bangkok Air)
Flies only from Suvarnabhumi airport, but both international and domestic. And flies to Chiang Mai, Chiang Rai, Hat Yai, Krabi, Lampang, Mae Hong Son, Pattaya / Uthapao, Phuket, Koh Samui, Sukhothai and Trat. International they fly to Bangladesh, Cambodia, China, Hong Kong, India, Laos, Malaysia, Maldives, Myanmar, Singapore, Taiwan and Vietnam.
Disclaimer : All information is created in good faith and is an expression of fair comment.