Retired U.S. Air Force Lt. Gen. Marc Sasseville, a decorated F-16 fighter pilot, looks back on the fateful day of September 11, 2001, when he and fellow pilot Heather Penney were tasked with intercepting United Airlines Flight 93, which had been hijacked by four al-Qaida terrorists. In an exclusive interview with ABC News, Sasseville shared his memories of that day and the determination it instilled in him to be prepared for future challenges.

Sasseville vividly recalled the sight of the Pentagon engulfed in flames and the heavy scent of burning concrete and airplane fuel. The attack on the Pentagon and the World Trade Center served as a motivating imperative for him to be prepared for any future threats. Drawing inspiration from the heroic response to the attack on Pearl Harbor in 1941, Sasseville acknowledged that the nation was once again faced with a significant challenge.

While uncertain of their mission initially, Sasseville and Penney were eventually given the chilling orders to locate and, if necessary, take down Flight 93. With their fighter jets, they were prepared to execute a daring plan that involved ramming the hijacked plane - a mission that was essentially a suicide mission.

Sasseville's decision was driven by his extensive training, feeling as if he was on autopilot. He and Penney agreed that Sasseville would target the front of the jetliner, while Penney would target the tail section. The gravity of their decision weighed heavily on Sasseville, knowing he had a wife and two young children waiting for him at home, unaware of the sacrifices he was prepared to make.

Fortunately, Flight 93 was ultimately overtaken by the heroic actions of the passengers and crew. They stormed the cockpit, regaining control of the plane before it crashed in Shanksville, Pennsylvania, resulting in the loss of all onboard. Sasseville expressed his gratitude for these true heroes, emphasizing that their actions altered the course of events and potentially saved his own life and that of his family.

Following their initial mission, Sasseville and Penney later discovered that their next assignment was to escort Air Force One as President George W. Bush returned to Washington. Photos captured by the press corps showed Sasseville's F-16 flying alongside the presidential jet's left wing.

Upon his return home, Sasseville kept his role on 9/11 quiet, hugging his family tightly and explaining that he would be away for an extended period due to the tragedy that had befallen America. Only later did his wife, Karin, learn of his heroic actions, expressing her admiration and pride for her husband's bravery.

Sasseville continued to serve in the Air Force, rising to the rank of a three-star general and becoming the second-highest-ranking officer in the National Guard. Now, after an outstanding 40-year career, Lt. Gen. Marc Sasseville officially retired from the Air Force. His last flight in an F-16 took place on May 15 from Joint Base Andrews, the same base where he and Penney took off on that historic day.

In a bittersweet twist of fate, the unarmed F-16 that Sasseville piloted on 9/11 has been reconfigured by the Air Force to serve as a target drone for pilot training purposes. Sasseville's retirement ceremony was attended by his wife and children, who joined him in celebrating his accomplishments and the difference he has made throughout his distinguished career.

Expressing gratitude for the opportunity to serve, Sasseville delivered a heartfelt speech, acknowledging the honor and privilege he experienced as a member of the Air Force. With a final farewell, he handed the torch to the next generation, ready to take on the responsibility of protecting the nation. To mark the beginning of his retirement, Sasseville and his family plan to take a well-deserved vacation in Puerto Rico, enjoying some much-needed rest and relaxation.