A domestic airline in Thailand has apologized after three friends of a pilot joked in a group chat about crashing the plane he was going to fly with former Prime Minister Yingluck Shinawatra on board.

The screenshot of the chat, conducted on their phones Sunday, somehow got leaked on social media, provoking widespread criticism of the airline, Nok Air. In response, Nok Air chief executive Patee Sarasin said in a tweet that "this kind of behavior is intolerable."

He says he "will personally call Yingluck and apologize." Nok Air has no politics and "I won't stand this," he said.

Yingluck came to power in a landslide election victory in 2011, but her government was ousted in a coup in 2014 after protracted political turmoil.