As of December 2020, the most expensive aircraft of the Thai Airways fleet is the Boeing 777-300ER.
20182022: Phase out all Boeing 747-400s and some Boeing 777s and acquisition of 15 next-generation wide-bodied aircraft to replace them. 3 777-300ER will be delivered from Boeing throughout 2021 - as the original delivery date was move forward due to COVID-19. The 3 aircraft will be fitted with Royal First Class to replace the first class demand routes as THAI plan to retire the entire Boeing 747-400s completely. 
