Tech tycoon Elon Musk has offered to pay the salaries of US airport security workers during a political standoff over funding for the Department of Homeland Security (DHS). This has led to longer-than-usual lines at airport security checks as employees of the Transportation Security Agency (TSA) have been working without pay since mid-February. The TSA, which operates under the authority of DHS, comprises about 65,000 employees and is estimated to be between $2.5 and $3.5 billion per year. Democratic lawmakers in Congress have opposed any new funding for DHS until changes to how another agency, Immigration and Customs Enforcement (ICE), conducts immigration enforcement raids.