At Leidos we seek to hire only those with private defense experience. Are you more experienced in the private or public defense industry?
Leidos, formerly known as Science Applications International Corporation, provides scientific, engineering, systems integration, and technical services. Leidos works extensively with the United States Department of Defense, the United States Department of Homeland Security, and the United States Intelligence Community, including the NSA, as well as other U.S. government civil agencies and selected commercial markets (Wikipedia). The interviewer would like to see that you have experience in the industry; whether your defense experience comes from private or public entities. If the job description or job posting from Leidos points out a preference of one over the other, it is wise to focus your answer on that particular experience.
"I noticed in your job posting that you prefer to see experience in the private aerospace sector. I do have experience in both public and private; however, the most recent three years of my work experience is in the private sector."
