An unidentified flying object (UFO) is something that people see flying in the sky but they can't figure out what it is. It's like when you see a bird flying, you know it's a bird, but sometimes people see things in the sky that don't look like birds or airplanes.
People get excited when they see a UFO because it's a mystery. They wonder if it's from outer space, like an alien spaceship or if it's something secret that the government is testing.
Sometimes, people think they see a UFO, but it really turns out to be something else. Maybe it's a balloon or a drone or even a planet or star. But sometimes, nobody can really explain what it is, and that's what makes it so interesting.
Scientists and researchers try to study UFO sightings to see if they can learn anything new. But even when they don't find any answers, it's still fun to imagine all the possibilities of what could be out there in the sky.