I can field this one because I am well acquainted with the guy who did the study for them that resulted in the decision to buy Chakri Narubet.

The ship isn't really an aircraft carrier in the sense that we think about that type of ship in the west. It was designed primarily for maritime patrol, search and rescue and disaster relief missions in the Gulf of Thailand with an air wing entirely of helicopters. The ships hull number "911" is not a coincidence. The alternative to get the same coverage as a carrier parked in the middle of the Gulf was to build a combination of multiple helicopter capable offshore patrol vessels and new land based maritime patrol aircraft and bases to operate them from.

The carrier was cheaper, and more flexible as well.

The original contract went to the now defunct German Bremer Vulkan shipyard but due to some contract shinanigans the order was cancelled and a new tender put out, this time won by the Spanish Izar yard with one of their standard designs based on the Spanish carrier Princepe de Asturias. As a deal sweatener the Spanish government threw in a batch of obsolete AV-8A "Matador" Harrier jets and the remaining supply of spare parts. The Thai's though had no requirement for the ship to operate fixed-wing aircraft and had not made any preperations to do so. These aircraft therefore have seen little use and don't operate from the ship. She strictly operates helicopters.

Unfortunately the delivery of Chakri Narubet coincided with the 1997 Asian Economic Crisis and a 50% reduction in the Thai military budget which the country has been slow to recover from and she does not spend as much time at sea as she should.