When someone reports seeing a flying saucer, there are only two possible reasons. Either they actually saw something which they couldn't recognize at the time, or they are making the story up! People need to worry more about distracted drivers and climate change than they do about whether someone saw a flying saucer or not.
UFO has been a science myth or fact question for many years. Till date there has been no proof about UFOs. Most of the cases have been illusion or people mistaking something else for UFOs. Airplane pilots, even they sound more technical source, may make a mistake considering light effects that occur in the sky. So, there shouldnt be a concern for something thats not been proven real.
Unless an intelligent life form was capable of traveling at a speed one from earth cannot, we would be able to detect a meteor, an alien or anything else well before it got to earth. Our technology is quite vast and extensive. Someone seeing a "flying saucer" shouldn't be taken serious.
UFOs are simply what their name states--unidentified flying objects. While the object is unusually like a flying saucer, there is no proof of what the object actually is, and therefore there should be no cause for concern. It is also important to remember, especially in this day and age of technology, that not all of the stories and images we see and hear are completely factual and genuine, and the images that have been released from this event could have very easily been tampered with.