Eighteen flights were affected. Though normal operations resumed an hour later, the incident captured the attention of the Chinese media and sparked a firestorm of speculation on the UFO's identity.
"It is a hidden U.S. bomber flying toward China," one Internet user wrote on Monday. Another wrote on Sunday night, "In my opinion, the UFO is neither a U.S. missile nor a Russian satellite. Suggestions that it is extraterrestrial are even more preposterous. Everyone, use your head. This is clearly a man-made phenomenon. Would the U.S. or Russia risk provoking China's anger by firing a missile or satellite rocket in Chinese skies, without warning? I believe the Chinese military is responsible for the UFO. It is a new missile or aircraft being tested out."
Fueling speculations further, Hangzhou residents released photos, taken in the afternoon before the delays, of a hovering object bathed in golden light and exhibiting a comet-like tail. Less than an hour before the Xiaoshan airport shut down, residents said they also saw a flying object emitting red and white rays of light.
Resident Ma Shijun was taking a nighttime stroll with his wife when he saw the object.
"I felt a beam of light over my head. Looking up, I saw a streak of bright, white light flying across the sky, so I picked up the camera and took the photo. The time was 8:26 p.m. However, whether the object was a plane, or whether it was Xiaoshan Airport's UFO, I don't have a clear answer," Ma told the Xinhua news agency.
The photos taken by Hangzhou residents may be unrelated to the UFO that shut down Xiaoshan Airport. According to Hangzhou meteorological authorities, residents in the afternoon probably saw light reflecting off of an airplane. As for Ma's nighttime photo, Beijing Planetarium curator Zhu Jing told Xinhua that the object looks just like a plane shining its strobe lamps.