Provides guidance to FAA personnel on interpreting and administering the continuing commitments airport sponsors make to the U.S. Government when they accept grants of federal funds or federal property for airport purposes. The handbook (i) analyzes the various federal obligations in legislatively mandated airport sponsor assurances, (ii) addresses the nature of the assurances and the application of the assurances in the operation of public use airports, and (iii) facilitates interpretation of the assurances by FAA personnel. Change 1 (dated 11/22/2021) updates Chapter 1, Scope and Authority; Chapter 9, Unjust Discrimination between Aeronautical Users; Chapter 10, Reasonable Commercial Minimum Standards; Chapter 11, Self-Service; and Chapter 23, Reversions of Airport Property. The FAA will continue to release changes until the entire document is updated.