Final Answer: What do you personally consider the most plausible explanation for the UFO phenomenon? Please explain why.

Haha, this question is arguably one of the ultimate mysteries. If I had to give the most probable explanation, I wouldn't simply bet on a single answer, because the UFO phenomenon itself is a 'hodgepodge'.

I personally believe that the most probable explanation for the UFO phenomenon is a composite model, mainly consisting of the following parts, ranked by likelihood:

Tier 1 (accounting for over 95% of cases): Misidentification and Man-made Aircraft

1. Mostly 'mistaken sightings': This accounts for the largest portion. There are simply too many things in the sky, making it difficult for ordinary people to distinguish them with the naked eye.

   • Natural phenomena: Such as very bright planets (Venus is often mistaken), ball lightning, atmospheric refraction illusions, or even flocks of birds or insects creating optical illusions under specific lighting conditions.
   • Man-made objects: This category is growing. Examples include weather balloons, sounding balloons, drones (nowadays in all sorts of strange shapes), LED kites, sky lanterns, reflective plastic bags, and the ubiquitous Starlink satellites. Many people see a string of moving lights at night and assume it's an alien fleet, when in fact it's just Musk's satellite constellation. Our brains are very good at 'filling in the blanks'; upon seeing a blurry light, they automatically imagine it as a structured, disc-shaped object.

2. The 'Undisclosed Secret' – Unrevealed Military Technology: This is the most compelling theory for explaining 'high-level sightings' (e.g., objects seen by fighter pilots performing incredible maneuvers).

   • The reason is simple: militaries worldwide, especially those of major powers, are undoubtedly secretly developing aircraft far beyond public imagination. Examples include hypersonic reconnaissance drones, spaceplanes, and new electromagnetic propulsion systems. When these are tested, their speed, maneuverability, and appearance are unprecedented. When they are detected by their own pilots, radar, or even adversarial detection systems, they naturally become 'Unidentified Aerial Phenomena' (UAP/UFO) because they cannot be explained by existing knowledge. The US military's recent acknowledgment of the authenticity of some videos is likely partly a 'desensitization' effort, to gradually accustom the public to new types of aircraft that might appear on future battlefields, and partly because they genuinely encountered things they themselves cannot explain.

Tier 2 (accounting for the remaining 5%): Truly Unknown Territory

After filtering out everything that can be explained by the above, there will always be a small handful of 'hard cases' that even top scientists and military analysts cannot explain with current knowledge. For these very few cases, I lean towards the following possibilities:

• Probes from extraterrestrial civilizations (the most likely 'unknown' explanation)
  • Reason: The universe is simply too vast, unimaginably so. The Milky Way alone contains hundreds of billions of stars; to suggest that Earth is the only 'lucky one' to have birthed intelligent life is, probabilistically speaking, extremely unreasonable. If civilizations exist that developed tens of thousands, hundreds of thousands, or even millions of years before us, their technological level would appear as 'magic' to us.
  • Why no direct contact? This is also easy to understand. Imagine a human research team observing a primitive tribe in the Amazon rainforest, or an ant colony. Would we walk up to the ants, say hello, and teach them how to build smartphones? No. We would observe, record, and study them from a distance, in a way that doesn't disturb them. Perhaps for a higher civilization, Earth is a giant 'nature reserve,' and what they send are merely unmanned probes conducting some form of long-term observation that we cannot comprehend. What we occasionally see might just be these probes inadvertently 'showing their hand'.

To summarize my personal view:

The UFO phenomenon is like a massive pyramid. The broadest base (over 95%) consists of various misidentifications and secret man-made objects. The tiny tip (perhaps less than 5%) represents truly unexplained phenomena.

For this small tip of the pyramid, I am willing to believe that it includes the possibility of civilizations from beyond Earth, far surpassing our current technological level. This is not blind faith, but a rational inference based on the vast scale of the universe and probability.

So, the next time someone asks me, I won't simply say 'it's aliens' or 'it's all fake.' I'll say: 'Most of it is misidentification, but for that small portion of true unknowns, it's best to maintain a sense of awe and curiosity.' This might be the attitude closest to the truth.