The Critical Infrastructure Airspace Defense Act empowers private owners and operators of designated critical infrastructure facilities to detect, track, and mitigate threats from unmanned aircraft systems (UAS). This authority, which overrides certain federal laws, is granted to address the growing risk posed by drones to vital assets such as nuclear generating stations and key components of the bulk power system, which currently lack clear statutory means to defend against such threats. To exercise this authority, personnel must undergo rigorous training and certification by the Department of Homeland Security, in coordination with the Department of Energy and the Federal Aviation Administration. The bill mandates the establishment of a national certification program within 180 days, focusing on legal, operational, and technical proficiency, and requiring mandatory coordination with the FAA to protect the national airspace system. Furthermore, the legislation creates a grant program , authorizing $250 million from fiscal years 2027 through 2031, to help critical infrastructure owners acquire and operate approved counter-UAS technologies. It also provides significant liability protection , deeming authorized actions as federal actions and shielding personnel from civil or criminal claims, except in cases of gross negligence or willful misconduct. This temporary authority is set to expire on September 30, 2031, with ongoing reporting requirements to Congress.