On June 28, Southwest will begin offering three daily non-stops between New York's LaGuardia and Baltimore-Washington Airport, which is about halfway between Baltimore and DC.
Regional airlines fly 64% of the takeoffs and landings at Chicago's O'Hare International, 74% at Seattle-Tacoma and 52% at New York's LaGuardiaAirport.
Last month's emergency occurred about three hours into controller Harten's eight-hour shift, but only 15 minutes after he was assigned to handle departures from New York's LaGuardiaAirport.