American Airlines said their reservation system is back online after a nationwide computer glitch prompted the carrier to ground all flights.
The airline said flights had resumed as of 4 p.m. Central time; however, it expected delays and cancellations to continue throughout the day.
Problems with the airline's computer system left some passengers stuck on the ground, while others could not make reservations.
As of Tuesday afternoon, American had canceled seven flights and delayed more than 50 others.
Meanwhile, the Federal Aviation Administration is holding all American flights headed to Dallas, Chicago's O'Hare Airport and New York's Laguardia airport.
Officials at Central Illinois Regional Airport say two departing flights, one to Chicago and one to Dallas-Fort Worth, were canceled but their overnight flight from Chicago will still arrive as scheduled.