OKLAHOMA CITY - Residents on the southwest side of Oklahoma City are trying to figure out what made a loud, roaring noise early Friday morning that interrupted their sleep for hours.

From about midnight to 2 a.m., News 9 received dozens of emails, phone calls and Facebook posts about the noise. People said it rattled windows and shook their homes.

Many compared the noise to a large jet engine, and the neighborhoods are near Will Rogers World Airport.

Friday afternoon, Will Rogers Airport confirmed the McDonnell-Douglas MD-80 was doing an "engine run-up" at the time.

Karen Carney with the Will Rogers World Airport said a client on the airport property, AAR, is a 24/7 operation and they were running the engine of the MD-80, which is a "family of twin-engine, short-to-medium-range, single-aisle commercial jet airliners."

Carney told Red Dirt Report that the testing has always been allowed, but the airport may have to reevaluate the rules due to increased complaints.