FAA’s planned furloughs of air traffic controllers are set to begin next week, prompting Airlines for America (A4A) to file a lawsuit Friday against the agency to prevent the furloughs and flight delays that are expected to result.

FAA has said it has no choice under US federal government mandatory spending reductions, known as budget sequestration, other than to furlough most of its employees for one day every two weeks. It has warned that the furloughing of controllers will lead to flight delays.

Speaking to reporters Friday, A4A president and CEO Nicholas Calio said the controller furloughs are “illegal, irresponsible and damaging“ and will cause “maximum destruction for the traveling and shipping public.” He said FAA’s decision to implement the furloughs was based on a “bad reading of the [sequestration] law,” adding, “We thought the controllers should be left alone and at the end of the day the FAA would find a different solution.”

A4A warned that “widespread ground stops” expected to ensue once the furloughs start will “cause delays of up to four hours at major hub airports, impact up to 6,700 flights a day and affect one out of every three passengers.”

A4A filed a motion in the US Appellate Court for the District of Columbia Circuit Friday seeking a stay to halt the controller furloughs and the resulting reduction in air traffic capacity they are expected to cause. The Air Line Pilots Association (ALPA) union and the Regional Airline Association (RAA) joined the lawsuit. “Air traffic controllers have never been furloughed, regardless of any budget cuts, and there is a reason for that—they are critical to maintain the safety and efficiency of the National Airspace System,” Calio said.