By Leslie Josephs, CNBC

Airport screeners are calling out sick in increasing numbers, while some workers are fretting about where their next paycheck will come from as a partial U.S. government shutdown enters its third week.

The impact from thinner ranks at the country's airports has had a minimal impact so far, according to the Transportation Security Administration, but the agency warned that travelers may have to wait longer at security lines. Standard wait times are 30 minutes for standard checkpoints, and 10 minutes for TSA's PreCheck.

"We have seen some call outs over the holiday period and they have increased, but are causing minimal impact given there are 51,739 employees supporting the screening process," the TSA told CNBC in a statement.

"Wait times may be affected depending on the number of call outs, however to date, screening wait times remain well within TSA standards," the statement read.

TSA agents, air traffic controllers and customs and immigration officials, which screen travelers coming into the country, are among the some 420,000 federal employees who are still required to work amid the shutdown without pay. Other employees were furloughed.

Unions representing air traffic controllers and pilots from JetBlue Airways, United Airlines, Delta Air Lines and other carriers have urged the government to come to a quick end to the partial shutdown. They complain that the impasse is hindering federal safety oversight activities.

Read the full story on the CNBC website.