In 2020, American Airlines and Republic Airways parked more than 100 planes at Pittsburgh International after the COVID-19 pandemic caused them to cut flights out of their schedules. Airport officials estimated they could store about 140 planes on unused taxiways, runways, deicing pads, and other surfaces. The parked planes included American's Airbus A319, A320, A321, and wide-body A330 aircraft, as well as American's smaller Embraer E-190 Republic's E-170 jets. Also due to the coronavirus, Spirit Airlines began flights between Pittsburgh and Arnold Palmer Regional Airport, about 60 miles away in Latrobe, Pennsylvania, as part of a triangular route to Orlando in order to consolidate passengers going to Orlando onto one flight. Alaska Airlines also modified its nonstop service from Pittsburgh to Seattle to begin in Baltimore, stop in Pittsburgh, and continue to Seattle. The airport became the first US airport to deploy robotic floor scrubbers that use UV-C light to disinfect high-traffic areas. The coronavirus pandemic led to severe drops in traffic from the airport, as much as 95%. It also led to the delay of the airport modernization project. Monthly enplanements bottomed out at 32,415 for the month of April 2020. Traffic rebounded somewhat over the summer and the airport finished 2020 with 3.649 million passengers.