When Japan invaded China in 1937, Chung volunteered as a front-line surgeon, but she was secretly assigned instead to recruit pilots for the 1st American Volunteer Group, better known as the "Flying Tigers." During the war, Chung would serve up to 175 people at Thanksgiving at her house and wrapped and addressed 4,000 gifts at Christmas. Her houseguests included high ranking officers and US senators and congressmen; leaning on these connections, she helped establish the Women Accepted for Volunteer Emergency Service although she was not permitted to join them, as the government suspected that she was gay. Mom Chung adopted the entire VF-2 squadron, nicknamed "The Rippers" for their logo, which showed a Chinese dragon ripping a flag. VF-2 was assigned to and would set an American record by shooting down 67 Japanese planes in a single day during the Great Marianas Turkey Shoot in June 1944.