The "Expanding Regional Airports Act" establishes a new grant program under the Secretary of Transportation to improve passenger and flight capacity at underserved regional airports. This program will provide financial assistance to eligible general aviation or nonprimary commercial service airports that serve communities with populations of at least 75,000 residents. The grants, ranging from 3 to 10 awards annually , can be utilized for a variety of critical infrastructure projects. These include runway lengthening , expanding passenger and property screening facilities, constructing hangars, and enhancing overall passenger amenities. Furthermore, funds may cover expenses related to complying with essential operational and security requirements, with $50,000,000 authorized for appropriation each fiscal year to support these vital improvements.