I clicked on the US Airways link and found this info:
Each year, US Airways receives thousands of donation requests from worthy organizations and individuals. To maximize the airline’s philanthropic reach, corporate giving guidelines have been established. Due to the volume of requests, coupled by limited resources, we support nonprofit organizations located in and providing services in the major metropolitan areas of Charlotte (Mecklenburg County), Philadelphia (Berks, Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties), Phoenix (Maricopa County) and Washington, D.C. (Alexandria, Arlington, District of Columbia, Fairfax-Falls Church, Loudoun, Montgomery, Prince George’s, and Prince William Counties). These cities represent the communities served by the airline with the greatest number of flights and employees.