The twin-engine aircraft that crashed in Nepal killed all 72 people on board.
The FAA was forced to ground thousands of flights last week after a mass outage of a key safety system.
A Delta flight was forced to abort takeoff as an American Airlines plane taxied across the runway, according to the FAA.
The FAA said its Notice to Air Missions system had “failed” and ordered all domestic takeoffs temporarily halted.
Southwest Airlines is now turning its attention to repairing its damaged reputation after it canceled 15,000 flights around Christmas and left holiday travelers stranded.
Gary Kelly steered Southwest away from its founding "culture and principles," the union's vice president wrote in a scathing letter.
The employee of Piedmont Airlines, a regional carrier owned by American Airlines, died in an incident involving a parked aircraft at an Alabama airport.
If Thursday is the last day of the Southwest crisis, it will be marked by about 2,350 canceled flights, nearly 60% of the airline’s schedule.
“We are past the point where they could say that this is a weather-driven issue,” the transportation secretary said.
Across the country, officials have attributed at least 18 deaths of exposure, storm damage and car crashes on icy and snow covered roads.