(CNN) -- Talk about eerie.
One of two recent UFO sightings in China occurred almost on the 63rd anniversary of news that a "flying disc" had been found in Roswell, New Mexico.
And like in 1947, people either choose to believe or be skeptical that visitors have stopped by from outer space.
Nothing has officially been ruled in or out by Chinese officials, who are looking into whether the objects were private or military aircraft, rocket flares, reflection in the sky or something else.
The first sighting occurred at Hangzhou's Xiaoshan Airport, in the eastern part of the country, according to the state-controlled Xinhua news agency.
Eighteen flights were delayed or rerouted and operations shut down after twinkling lights were spotted above the terminal around 9 p.m. July 7, the agency said. According to Xinhua, speculation has centered on a private aircraft. The state-run China Daily quoted a source saying the object had a military connection.
"No conclusion has yet been drawn," said Wang Jian, head of air traffic control with Zhejiang branch of the Civil Aviation Administration of China, and the investigation continues.
Purported photos of the unworldly object have appeared online and on YouTube.
Meanwhile, The Shanghai Daily reported a UFO appeared above the city of Chongqing on Thursday.
Witnesses said four "lantern-like objects forming a diamond shape" hovered for an hour above a park.
"I stared at it and it did not move," one resident told the newspaper. "After hovering for an hour, the thing started to fly higher and finally out of people's sight."
UFO sightings around the world are common, but a little rarer in China.
The International UFO Museum and Research Center in Roswell, New Mexico, educates visitors, conducts research and receives sighting reports.
Its website summarizes the Roswell incident, which came to light July 8, 1947. "Once it became public, the event known as The Roswell Incident, the crash of an alleged flying saucer, the recovery of debris and bodies and the ensuing cover up by the military was of such magnitude and so shrouded in mystery, that 60 years later there are still more questions than answers."
The U.S. government has long contended that no aliens or spaceships were found.
Mark Briscoe, library director for the museum, said the center looks for credibility whenever it records UFO reports, including a documented date, time and location. He sees many photos, and an outside researcher provides information.
"You can tell some of them are a little different. A little off," Briscoe said of some UFO submissions. But he recently recorded 300 he found to be credible.
He said one of the photos circulating about the Chinese airport could be legitimate, but he had not seen the others.
The blog Forgetomori weighed in on Internet and news media images purporting to be from Xiaoshan Airport.
"All of these other photos, with the exception of a single one, are also simply long-exposure photos of aircrafts, but in this case, helicopters," the blog says. "Not only that, they have nothing to do with China and were published on the web long ago."
CNN's Helena Hong and Journalist Annie Tai contributed to this article.