S3 International, LLC
Aviation and Aerospace Component ManufacturingWisconsin, United States51-200 Employees
S3 International, LLC, operating as S3 AeroDefense, is an aviation and aerospace component manufacturer and sustainment provider. Based in Milwaukee, Wisconsin, and founded in 2005, it maintains a diverse, multilingual team with extensive aerospace knowledge to support global military operators through spares distribution, repair and overhaul, and program management. Its customer base spans military and commercial aerospace clients worldwide seeking reliable spares and related services. The company collaborates with a broad network of OEM partners and supports platforms across fighters, rotorcraft, transports, and patrol aircraft. In 2025 it earned the FAA Aviation Maintenance Technician Employer Diamond Award of Excellence, reflecting a commitment to technician training and professional development.