Not green, multiple eyed, strange figures, but people.
One form of "aliens" in society are immigrants. These people are often refereed to as illegal aliens, meaning they came into the United States illegally. These people are often looked down upon and not excepted. Acceptance is key to unity. Helping these people become legal and helping them get jobs would open up new opportunities for these people. Put yourself in these peoples shoes and open your mind.
Another form of alienation is the way we teenagers treat each other. Its not as serious ad moving to another country, but it can have a negative impact. Teens like to exclude others, and be extremely rude, making people feel like aliens. Some feel like they are from another planet because of how they are treated. Instead of excluding, include. Be kind to another person, love another person, make them fell welcome. We are all from Earth, let's make sure we make others feel like it.