Just two of the United States’ “big three” air carriers still host the Boeing 777-300ER on their flightlines: United Airlines and American Airlines. The iconic widebody twinjet is a staple of long-haul aviation and a trailblazer of ETOPS (Extended-range Twin-engine Operation Performance Standards).

Airlines are scaling back flights at dozens of major U.S. airports to ease the pressure on air traffic controllers, who have been working unpaid and under intense strain during the ongoing government...

Analysts warn that the upheaval will intensify and spread far beyond air travel if cancellations keep growing and reach into Thanksgiving week.