Yes, you may declassify aircraft (See §§102-33.415 and 102-33.420).

(a) A declassified aircraft is no longer considered an aircraft, but may be considered as a group of aircraft parts or other property for ground use only.

(b) You must retain documentation and traceability on all parts that are intended for use as replacement parts on other aircraft. You must carry such “aircraft parts or other property” on your property records under the appropriate Federal Supply Classification group(s) (e.g., miscellaneous property).

(c) For disposal of the property remaining after declassification of an aircraft, you must follow the property disposal regulations in 41 CFR parts 102-36, 102-37, 102-38 and 102-39.