Over the weekend, some airports had long lines at checkpoints, apparently caused by a rising number of security officers calling in sick as they face the prospect of missing their first paycheck this week.
Safety inspectors aren't even on the job. A Federal Aviation Administration spokesman said Monday that inspectors are being called back to work on a case-by-case basis, with a priority put on inspecting airline fleets.
So far, the most visible signs of the shutdown — in its 18th day Tuesday — include the closure of some government buildings and national parks and trash overflowing bins on the National Mall in front of the Capitol.