A top TSA official, Adam Stahl, has warned that airport security problems are likely to worsen before they improve due to the ongoing Department of Homeland Security shutdown. Stahl warned that airports may have to suspend operations due to mass callouts, which have led to widespread flight disruptions. He also criticised Congress for holding the agency hostage. The shutdown, which is in its fifth week, has left about 50,000 Transportation Security Administration officers working without pay since mid-February. More than 5,000 flights nationwide were delayed on Thursday, and Delta Air Lines CEO Ed Bastian described the situation as "inexcusable".