Haiphong police said the incident occurred late on June 6 when the crew of a Vietnam Airlines flight from Ho Chi Minh City reported spotting an unidentified flying object at an altitude of about 200-300 feet near the airport's runway.
Air traffic controllers subsequently observed a glowing object moving up and down across the approach area and immediately activated procedures for handling unauthorised flying objects within restricted airspace.
The object was later identified as a lighted kite and removed shortly before midnight, restoring normal airport operations.
The incident affected three flights, including one departing service and two inbound flights that were forced to divert to alternate airports.
Authorities warned that flying kites, drones or other airborne objects near airports poses a serious threat to aviation safety and may result in administrative fines ranging from VND 1 million to VND 40 million.
Violators could also face criminal charges if their actions cause serious consequences, police said.
People are urged not to fly kites, drones or other airborne objects near airports and to report violations to authorities.