; (C) an assessment of whether air carriers operating under part 121 of title 14, Code of Federal Regulations, would purchase post-2017 aircraft for commercial purposes; and (D) an assessment of the economic need of scheduled airline service of small and rural communities and the longstanding challenges of improving scheduled service to these communities. (e) Definitions In this section: (1) Pre-1995 aircraft The term pre-1995 aircraft means passenger aircraft with at least 10 and not more than 19 seats that were certified under part 23 of title 14, Code of Federal Regulations, before March 29, 1995, and that operate under part 121 of such title. (2) Post-2017 aircraft The term post-2017 aircraft means passenger aircraft with at least 10 and not more than 19 seats certified under part 23 of title 14, Code of Federal Regulations, after August 30, 2017.