Hundreds of flights were canceled and thousands more disrupted across the US Northeast on Monday after a major communications failure brought air traffic at some of America’s busiest airports to a standstill. The Federal Aviation Administration (FAA) restricted incoming flights after a primary communications circuit at its Philadelphia air traffic control facility failed. The problem became more serious when officials discovered that a backup fiber-optic line had been accidentally severed during construction work in New Jersey. The disruption affected travelers at major airports serving New York, Philadelphia and Boston and created ripple effects across the country. Operations gradually resumed after repairs, but passengers continued to face delays and cancellations as airlines worked through the backlog.