What are the CAP policies on knives both at CAP meetings and during CAP emergency services missions?

Sheath knives may be worn during your participation on emergency services missions, but there are some limits and some knife types are prohibited. Swiss Army knives, Leatherman or Gerber multipurpose type tools are recommended. Always check to make sure you are compliant with local laws.

The following guidance comes from GROUND & URBAN DIRECTION FINDING TEAM TASKS

e. Restrictions on Knives: You may only wear a sheath knife if authorized by your team leader. Sheath knives cannot have a blade longer than 6” or a total length of greater than 11”. The sheath must adequately secure the knife and protect the wearer from the blade. If authorized, sheath knives will be worn only on the pistol belt or carried inside the pack. The following knife types are not authorized: boot knives, butterfly knives, switch blades, double edged knives, “Rambo” style survival knives, or knives with retracting sheaths. Machetes or hatchets can only be carried by senior members when needed for that specific sortie. No knives may be visible when the member is performing crash sight surveillance duty.
Knives may also be used for some aerospace education constructions. The regulation that governs cadet participation at CAP meetings, CAPR 52_16, is silent on the subject, but there is typically no on-going need for cadets to bring knives to regular CAP meetings.

Also see guidance below Paragraph 2 of CAPR 900-3.
2. Other Dangerous Weapons. Other than as provided for in paragraph 1 above, members engaged in CAP activities are prohibited from possessing or using weapons as defined by local state statutes as "dangerous."