Planet Airlines; Travel and More
History: On the 20th May 2011, the Thai Airways board announced plans to create a new lower-cost airline, at the time dubbed Thai Wings. It planned to begin operations in July 2012.Thai Smile is intended to serve the market gap between low-cost carriers and full service airlines. The name Thai Smile was chosen from a pool of 2,229 entries in a contest to name the airline.

Soruce: Wikipedia
Operations: Thai Smile bases it's aircraft at Bangkok Suvarnabhumi Airport (BKK), after a change of strategy to compete with the low cost airlines at the other airport Bangkok airport (DMK), and therefore now it can streamline connections from the major airline and offer smooth transits to it's passengers coming from further away. At the same time Thai Smile has positioned itself as a major player in the competitive markets at home and abroad with frequent flights to Cambodia, Myanmar, Malaysia and China. It also flies as far as Bangladesh and India. 
In the domestic market, Thai Smile flies to Chiang Mai, Chiang Rai, Phuket, Krabi, Koh Samui, Hat Yai, Narathiwat, Ubon Ratvhathani, Khon Kaen, Udon Thani and Surat Thani. 
Fleet: The airline uses entirely Airbus A320-200 aircraft with a few rows at the front for Smile Plus passengers( Business Class)  whilst the rest of the cabin is all economy seats with capacity for up to 174 people. 

Personal Review:

Fresh new airline in Thailand with a young and friendly crew. Limited reach of destinations offered out of Thailand.
Excellent service and hospitality with a smile.No millage redemption by Star Alliance airlines. (Except Thai Airways)
Airline backing by it's parent company Thai Airways International
Low cost airline with a difference: 20kg Baggage, free seat selection at booking time and light meal and drink included for free. 
 Millage redemption with Thai Orchid Plus Programme. 
 Clean and comfortable planes. 
 Reasonable fare prices and convenient times. 
 Departures from the main airport in Bangkok (BKK)
 Possibility for baggage transfer when flying to/from with Thai Airways.

Thai Smile Photoshow: