U.S. airline stocks dipped in premarket trading on Monday as a major winter storm caused widespread flight delays and cancellations. Shares of JetBlue, Southwest, Delta, United, and American Airlines all declined, with American particularly hard hit, seeing roughly a fifth of its flights cancelled.

The severe weather, affecting 118 million people across the eastern U.S., prompted federal emergency declarations. Flight tracking service FlightAware reported 3,662 cancellations and 818 delays for Monday, echoing disruptions not seen since the pandemic. Major hubs like Boston, New York, and Dallas faced significant operational challenges.

The storm is expected to move into the Atlantic on Monday, but icy conditions will linger. For investors, the event highlights the sector's vulnerability to weather-related shocks, which can quickly erase earnings and impact quarterly guidance. Airlines now face a recovery period to clear backlogs and manage costs.