; program extension (a) Use of modeling and simulation tools Section 44803(b) of title 49, United States Code, is amended— (1) in paragraph (11), by striking the period at the end and inserting ; and ; and (2) by adding at the end the following new paragraph: (12) use modeling and simulation tools to assist in the testing, evaluation, verification, and validation of unmanned aircraft systems. . (b) Program extension Section 44803(h) of title 49, United States Code, is amended by striking September 30, 2023 and inserting September 30, 2028 . 6. Extension of special authority for unmanned aircraft systems (a) Sense of Congress It is the sense of Congress that— (1) the lack of appropriate certification standards, rules, and processes set by the Federal Aviation Administration for airworthiness determinations and operational approvals of unmanned aircraft systems (as defined in section 44801 of title 49, United States Code) puts the United States at a disadvantage in global competitiveness and delays the integration of promising new technology into communities in the United States; (2) this lack of progress on a standardized airworthiness and operational approvals approach compels the extension of authority to issue exemptions under section 44807 of such title 49; and (3) such section 44807— (A) should continue to use a risk-based approach to authorize operations that do not fit within part 107 of title 14, Code of Federal Regulations