Most people know that Thai uses widebodies flying nearly all of their international flights. Unlike Singapore Airlines, they still own some narrowbodies, operated as Thai Smile. This leaves passenger having a hard time knowing which Thai aircraft is the best. Per Routesonline, Thai is planning to use their A350 on various routes. Thai A350 Here are the changes Bangkok – Denpasar TG431/432, replacing 777-300/-300ER in W17 Bangkok – Seoul Incheon TG658/659, replacing 747-400 in W17 Bangkok – Tokyo Narita TG642/643, replacing 777-300/-300ER in W17 While Thai's 777-300ERs has a great onboard hard product there 300s don't, so Denpasar and Tokyo Narita is a simple upgrade. However for the 747-400s while they are flying short routes eg: Singapore - Bangkok, they marketed their First class as Business Class with Business Class service, I am not really sure what Thai market there Seoul 747's First Class.