There's been a buzz in the air this week -- literally -- about a video allegedly showing a UFO flying near a passenger plane over Seoul, South Korea.

The video, which has been viewed several million times, has brought out a myriad of theories to explain the strange-looking oval white object viewed on Saturday. When a passenger on the airline tried to zoom in on the object with a video camera as it moved upward from the ground, pacing near the plane, it suddenly flew away.

Was this an alien visitation, a computer-generated image, a water droplet on the plane window or a white plastic bag moving in the wind?

As skeptics and true UFO believers battle it out over the origin of this latest unexplained object, they are engaging in an unresolved decades-old debate: Can unexplained UFOs become a safety issue for the commercial airline industry?

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