This appears to be related to the ATC issues caused by the government shutdown, given this first paragraph:

SUMMARY: This Order reduces or temporarily prohibits certain operations in the navigable airspace to ensure the safety of aircraft and the efficiency of the National Airspace System (NAS). To maintain the highest standards of safety in the NAS, certain air carriers will be required to reduce by their total daily scheduled domestic operations between 6:00 a.m. and 10:00 p.m. local at each airport by 10 percent, subject to the provisions set forth in this Order, in addition to other operational reductions in the NAS.