But Delta spokeswoman Betsy Talton said Monday: "Our information is it was a five-hour delay."
She said passengers may have been including the time it took them to board and then disembark at the gate.
Talton says thunderstorms on Sunday forced the FAA to ground flights at John F. Kennedy International Airport for six hours.
She says the Flight 621 crew decided to return to the gate after waiting in a take-off line for 3½ hours.
Because of congestion at the airport, the return to the terminal took another 90 minutes.
Delta spokesman Kent Landers told the Daily News that passengers are usually returned to the gate, but was unable to explain why passengers aboard the Las Vegas-bound flight were made to wait on the plane.
Landers says the airline will refund passengers and make new arrangements for them to continue their travels.