Piyasvasti joined Thai Airways in October 2009 when the carrier was in financial trouble. He continued to implement the turnaround plan and introduced a long term strategic plan where the financial position of the company was substantially strengthened, embarked on the largest aircraft acquisition and retrofit program ever implemented at Thai Airways, and formed Thai Smile as a first step in competing with low cost airlines. In June 2012, the board of directors suddenly voted Piyasvasti out with no explanation in what was seen as a politically motivated coup.
Piyasvasti joined Thai Airways in October 2009 when the airline was experiencing financial difficulties. He continued to implement a turnaround plan and introduced a long-term strategic plan that significantly improved the company's financial position, embarked on the largest aircraft acquisition and retrofit program ever undertaken by Thai Airways, and established Thai Smile as a first step in competing with low-cost airlines. In June 2012, the board of directors unexpectedly removed Piyasvasti without explanation, which was perceived as politically motivated.