In an exclusive interview with ABC News, retired U.S. Air Force Lt. Gen. Marc Sasseville shared the gripping details of a mission he thought could have been his last. As part of the response to the devastating terrorist attacks on September 11, 2001, Sasseville and fellow F-16 pilot Heather Penney took to the skies in an attempt to intercept United Airlines Flight 93, which was headed for Washington, D.C.

Sasseville vividly recalled the chaos and destruction that unfolded that day. As the Pentagon burned and the smell of airplane fuel lingered, he felt an urgent sense of duty to protect his nation. Together with Penney, they made the heart-wrenching decision that, if necessary, they would use their fighter jets as weapons, risking their own lives to prevent further tragedy.

Their training kicked in, and Sasseville prepared to target the front of the hijacked jetliner, while Penney would aim for the tail section. Unbeknownst to their families, Sasseville had a wife and two young children at home. Their bravery and sacrifice were driven by the determination to preserve innocent lives.

However, before Sasseville and Penney had the chance to intercept Flight 93, the passengers and crew on board took matters into their own hands. They bravely fought back against the terrorists, ultimately regaining control of the plane. The aircraft tragically crashed in an empty field in Shanksville, Pennsylvania, claiming the lives of everyone aboard.

Reflecting on that pivotal moment, Sasseville expressed deep gratitude to the heroes on Flight 93, emphasizing that their actions changed the course of history. Without their intervention, the outcome could have been immensely different for him and his family.

Following the events of 9/11, Sasseville continued to serve in the Air Force, rising through the ranks to become a highly respected three-star general and the second-highest ranking officer in the National Guard. After an extraordinary 40-year career, Lt. Gen. Sasseville officially retired from the Air Force on Wednesday, May 15.

In a retirement ceremony attended by his wife, Karin, and their children, Sasseville spoke humbly and thanked his colleagues for the opportunity to serve his country. He remarked on the honor and privilege of making a difference, and urged those in attendance to continue the important work.

As Sasseville embarks on this new chapter of his life, he plans to spend quality time with his family in Puerto Rico, taking a well-deserved break and indulging in hobbies like golf. As he reacquaints himself with a "normal life," Sasseville's commitment to the country remains, and his heroic actions on that fateful day in 2001 will forever be remembered as a testament to courage and selflessness.