American Airlines Group

American Airlines slipped two spots on 2019's Fortune 500 ranks, ceding its title as the leading airline in the U.S. to Delta, in an uneven year marked by labor disputes and the grounding of the Boeing 737 MAX planes. The latter caused the airline to cancel 10,000 flights in the fourth quarter alone. While the carrier's profits did rise 19%, to $1.7 billion, on $45.8 billion in revenues (up 2.8%), its hopes for a stronger showing in 2020 have since been scuttled by the coronavirus. After losing $2.2 billion in the first quarter alone and accepting government aid, American is shrinking its passenger fleet, the world’s largest. “Never before has our airline, or our industry, faced such a significant challenge,” CEO Doug Parker said in April.