Upvote:4
The Department of Homeland Security's Customs and Border Patrol uses a system called CAVSS (Centralized Area Video Surveillance System) and in 2018 was evaluating IDVRS (Incident Driven Video Recording System) which are body-cams for individuals.
The length of time CAVSS recordings are kept are listed in the Privacy Impact Assessment PDF, Section 5.1, available at the first link.
Whether or not they've actually installed surveillance in ALL airports I don't know, and I'm not certain they will make this information public.