The key is identifying the article the part is designed and suitable for use with. Parts principally used on powered manned aircraft or helicopters go under 880730, while parts for balloons, gliders, unmanned aircraft, or other aircraft not covered by the manned-aircraft headings go under 880790. When a part is interchangeable across types, the General Rules of Interpretation and any applicable CBP rulings govern.

Certain aircraft parts can be subject to antidumping or countervailing duty orders depending on the specific component and country of origin. Section 301 measures may also apply to parts sourced from particular countries. Always check the specific 10-digit tariff line and origin before entry, as measures attach at that level rather than to the heading as a whole.