A computer failure has delayed the departure of all Delta Airline flights scheduled for Monday morning, the company said in a statement.
"Delta has experienced a computer outage that has affected flights scheduled for this morning. Flights awaiting departure are currently delayed. Flights en route are operating normally," the US-based airline said.
Delta urged travellers "to check the status of their flights this morning while the issue is being addressed".
Delta did not provide any information on what caused the computer problem, or comment on how long it would take to fix.
On Twitter, Delta representatives urged patience as they dealt with a flood of messages from concerned passengers.
"All our flights are grounded due to the outage," read one tweet.
"We're experiencing a system-wide issue," read another tweet, apologising for the inconvenience.