Air force commander Prajin Juntong will relinquish his position as chairman of Thai Airways International (THAI), in a example other state agencies controlled by the Transport Ministry should follow.
ACM Prajin said on Tuesday he would tender his resignation on Thursday ahead of a board meeting scheduled for Friday.
His decision was to end criticism that he wanted to hold on to the position after the junta seized power from the government on May 22.
ACM Prajin is a deputy chief of the National Council for Peace and Order (NCPO) led by army chief Prayuth Chan-ocha.
He took over as chairman of the airline's board in March after Ampon Kittiampon was forced to step down amid rising opposition to his leadership by THAI staff, although he remains a member of the board.
ACM Prajin is still a board member of PTT Plc.
The ministry oversees many state-owned agencies — Airports of Thailand Plc (AOT), the State Railway of Thailand, Aeronautical Radio of Thailand, Port Authority of Thailand (PAT), Transport Co, Bangkok Mass Transit Authority, Mass Rapid Transit Authority of Thailand and the Expressway Authority of Thailand.
All have board members handpicked by the Pheu Thai Party.
ACM Prajin wanted to send a signal to other board members in other agencies appointed by the Pheu Thai-led government to resign, the source said.
Sqn Ldr Sita Divari was the first board member of a state-owned agency to resign after the coup. He stepped down on June 6, along with three other board members of AOT.
A source at the AOT said the remaining 11 members of the board decided to bring forward the next meeting to Wednesday, from Friday, to promote vice-chairman Araya Ngampramuan to be new chairman.
ACM Araya is the chief adviser of the Royal Thai Air Force, according to the AOT website.
Two more AOT board members — former Pheu Thai member Thirachai Wutthitham and Thanin Ungsuwarungsee - will follow Sqn Ldr Sita's example this week, the source added.
The three are all linked to Pheu Thai.
Kamronwit Thoopkrachang, who chairs the PAT board, said he is ready resign but did not want his resignation to disrupt the work of the port agency.
He and other board members would step down if they were pressed by the NCPO, Pol Lt Gen Kamronwit said.
''The PAT board had held talks and already informed the NCPO about their readiness to resign, to allow a new board to take over their duties,'' the former Metropolitan Police Bureau chief added.
Pol Lt Gen Kamronwit, another close link to Pheu Thai, was moved to an inactive post at the Royal Thai Police Office after Gen Prayuth launched his coup.