In the NAICS hierarchy, 33641 is the sole five-digit industry group within the 3364 subsector, so their scope is effectively identical. The distinction matters primarily for statistical reporting: federal agencies and trade databases may publish data at different hierarchy levels, and users should confirm which level a dataset uses before comparing figures.

The six-digit codes beneath 33641 separate civilian aircraft, engines, and parts (captured in the 33641X aggregate) from guided missiles, space vehicles, and their propulsion systems. Trade professionals analyzing import or export data should drill to the six-digit level to isolate civilian versus defense-oriented flows.