Do people really travel by themselves?

Yes people travel alone.  Why are you so concerned about this do you suspect he is doing something illegal...

to the dumb answer above it was about people in general because I know of 1 person not everyone who travels. That was the reason for the question. Janet and Jackson if your nasty.

Since you already knows he travels by himself, WHY are you asking us if people really travel by themselves?

Absolutely... I love travelling by myself. I traveled through Australia, America, Indonesia and the UK by myself. Best way to travel. You do what you want when you want, don't need to consider anyone else and meet interesting people along the way. 

I have no idea why the question Do people really travel by themselves has anything to do with your relation with a neighbor. 

Many people travel by themselves. For fun, for serenity, to relax. 

My daughter’s friend has a high stress job as a paramedic in a big city. He often has 3-4 off of work. He make good money and lives alone.   He takes off on adventure often. Many time unplanned. Most times alone. 

As soon as the weather gets good my friend takes off on his bike. He travels alone.  

This isn’t that uncommon. Especially for people who are single. 

He's not hurting anyone so who cares? If he enjoys it let him.

Sure they do. I travel often for business on my own, and I really enjoy it. I don't have to negotiate with another person about where to go and what to do. I eat where I want to eat, and do what I want to do. Your friend probably feels like that, too.