A close call between a Delta Air Lines Airbus A319 taking off from Ronald Reagan Washington National Airport and a US Air Force T-38 jet, often used by the military for training, sounded alarms in the cockpit of the passenger plane Friday.

A Delta Air Lines flight had a reported close call Friday with a U.S. Air Force jet near Ronald Reagan Washington National Airport. CNN first reported the close call between the Airbus A319 that was departing Reagan and an Air Force T-38 jet, which is often used for training.

According to a recording of air traffic control communications, Delta’s pilot asked, “Was there an actual aircraft about 500 ft below us as we came off of DCA?”