The NYSE Arca Airline Index, which tracks mostly U.S. airlines, is up 51% year to date through Monday, outpacing the S&P 500's 16% gain.
From June 24 through July 2, United had the biggest share of delays of U.S. carriers, accounting for 42% of its mainline schedule, according to FlightAware. "Airlines, including United, simply aren't designed to have their largest hub have its capacity severely limited for four straight days and still operate successfully," Kirby said in aHe said the airline will have to reduce its schedule in Newark, particularly during the spring and summer thunderstorm season to avoid pileups unless there is more capacity at the airport.