The Federal Aviation Administration is reducing flights across 40 major airports because of shortages of air traffic controllers triggered by the ongoing federal government shutdown.

The shutdown, which has gone on for over 40 days since Oct. 1, has forced about 13,000 air traffic controllers and 50,000 security screeners to work without pay.

The FAA has reduced flight volume by about 6% because of safety concerns, though according to data from Flightaware, some airports are experiencing far greater impacts than others.

Over the weekend major international airports saw flight cancellations spike. Here's a look at those impacted the most:

According to data from Flightaware, these 38 of the 40 airports impacted by FAA flight reductions because of the shutdown saw high numbers of cancellations from Nov. 7 through 11:15 a.m. on Nov. 10: