Air traffic control staffing issues are impacting flights for a second straight day at numerous U.S. airports as the partial government shutdown reaches its seventh day, the Federal Aviation Administration said in a notice on Tuesday.

Flight delays reported across multiple U.S. airports as unpaid essential workers call in sick during government shutdown.

As past shutdowns dragged on, FAA and TSA employees began calling out sick in significant numbers as they started to miss paychecks. Those absences were considered key factors in ending previous shutdowns as travelers started to feel the impact at airports.