American Airlines flights have resumed after a nationwide ground stop was issued for less than an hour Tuesday evening due to an IT outage, the airline said. Systems are coming back online now and flights are departing again," American Airlines said in a statement on X. While it was not immediately clear what caused the outage, the airline said a temporary ground stop was put in place while teams worked to resolve the issue. The ground stop, issued around 6:30 p.m. Thunderstorms forced ground stops at airports across major cities, including New York, Newark, Washington, DC, and Baltimore.