What is the right concept of aliens in Islam?
Should we believe in aliens or not?
Do they exist according to Quran and Hadith?
In stack overflow servey, I have to answer the question in the tittle.
there is no direct mention in Quran nor Hadith of the existence of an intelligent life in other planets. But also there is no mention of them not existing too. Although some scholars interpret some verses as a possible proof such as the one Sayyid mentioned in the comments.
Note:The next paragraphs are totally from my own perspective and my personal opinion. Please don't consider them a fatwa.
From my own point of view as a muslim, There are two reasons that make me believe such thing. Either it is in Quran or Hadith(which what you're looking for) or if it's a scientific fact or something sensible and perceptual that can't be denied. So not having information in Quran and Hadith gives me The choice to believe what I think it's true.
I personally Don't at all deny the possibility of the existence of intelligent beings in this massive universe. But at the same time I don't have any evidence that makes me say they 100% exist. This last paragraph would be my answer to the question.
I would like to know what you think.