A Kongming lantern, or sky lantern, caused delays at the Beijing Nanyuan Airport on Saturday night after becoming stuck in the engine of an airplane, the airport confirmed on Sunday.

Information about the incident was first released on the Sina Weibo account of a civil aviation maintenance forum on Saturday night, posted along with a photo showing a broken sky lantern on the engine vane of an airliner at the airport.

The airplane eventually took off after checks revealed there was no damage to the aircraft.

With the Lantern Festival approaching, the airport has warned people not to release Kongming lanterns or drones near its runway clear zone.

A Kongming lantern is a small hot-air ballon made of oil paper, which rises into the air due to a small flame warming the air inside and thus lowering the density of the lantern. People release the lanterns to make wishes, especially during the Mid-Autumn Festival and Lantern Festival celebrations.

An aviation professional who declined to be named told Beijing News that sky lanterns, drones and kites pose safety risks to aircraft in runway clear zones, as they can interfere with a pilot's vision or come into contact with aircraft.

Changshui International Airport in Kunming released a statement on Sunday, saying that it had experienced numerous cases involving illegal unmanned flying objects in the airport's runway clear zone recently, adding that its public security department is conducting an investigation into the issue.

According to Legal Evening News, an unmanned drone entered the runway clear zone at Mianyang Nanjiao Airport in Sichuan province on Feb. 2, causing three airliners to be diverted and five flights to be delayed. The airport resumed regular services two hours later.

Meanwhile, unmanned flying objects caused delays to departures and arrivals at Shuangliu International Airport in Chengdu on May 28 and Aug. 2 last year, the paper reported.

According to China's Civil Airport Regulation, it is illegal to release birds or fly unmanned balloons and other flying objects in an airport's runway clear zone.

Many provinces and regions, such as Yunnan and Beijing, have released detailed aviation regulations banning the launching of fireworks or the flying of drones and balloons in airports' runway clear zones. Those who violate laws may be fined between 20,000 and 100,000 yuan (US$3,000 and US$15,000).

In January, the Ministry of Public Security released a draft regulation to punish those who violate public orders, which states that those who ignore State regulations on flying all-purpose aircraft, including drones and powered paragliders, or other objects such as balloons, will be taken into custody for five to 10 days. In cases of gross violations, offenders will be taken into custody for 10 to 15 days.