The idea of courage in Mother 1 and 2 is probably best personified by the Flying Men. But courage is a concept with different interpretations. One can be courageous for many different reasons; there’s noble courage, reckless courage, foolish courage, even. And we see these different forms of bravery through the nature of the Flying Men:

Let’s start with EarthBound. Ness’ personal encounter with the Flying Man takes place just outside the Sea of Eden. When spoken to, the Flying Man says, "I am your courage," and joins Ness on his way to the Sea. But if you continue to bring the Flying Men along, and allow them to be killed, they will eventually become angry, and accuse you of mistaking desperation for courage. Are the Flying Men right? Could Ness possibly be desperately recruiting them out of fear for what lies ahead in Magicant? Keep in mind, this is also the first time Ness has ever been alone since the very beginning of the game. And now, suddenly he finds himself trapped in his own mind, with his three friends nowhere to be found. Magicant is a scary place, but it also teaches Ness that sometimes one must be able to rely on his own might, rather than the power of others. And with that, Ness learns an important lesson about true courage: the will to protect oneself and others from evil, in spite of dread or uncertainty. With this wisdom, he is able to defeat the Nightmare and conquer his fears and doubts. This triumph is what allowed Ness to transition from a normal boy to a true hero, and it definitely played a role in the final battle against Giygas.

Now let’s talk about Mother. The Flying Men appear there as well, only this time they were implemented by Maria in order to protect Ninten. This is very similar to George creating the robot EVE to protect his great-grandson. They will tell you that their sole purpose is to protect you, but why? Well, in this scenario, the Flying Men might be better described as a representation of Maria’s maternal instinct. I mean, their very creation was for the intention of assisting Ninten on his quest, so perhaps Queen Mary can subconsciously recognize her great-grandson. This would explain why everyone in Magicant "loves" Ninten, and helps him by giving him items and other means of aid. Maria may have been lending Ninten her courage in order to help him, and this courage naturally took the form of the Flying Man, just like how her love took the form of a melody...

-AmateurGamer

Flying Men are a small part of the world inside your mind... So, it's painfully obvious what each Flying Man represents. Courage, you say? Well, you are WRONG.

Flying Men lie in the area connecting the central stomach to the deepest darkest bowels of your mind... Everything you eat eventually goes to your bowels right? Well, that is what a Flying Man is...

Have you ever been hungry for chicken? Or pork? Or octopus? Well, probably not that third thing, but you get the general idea... There aren't just Flying Men, there are also Spaghetti Men, and Cookie Monsters... and Veggie Monsters, but we try to forget that they exist. Everything you are every hungry for is created magically in your mind. This magic can't be taken to the real world, because it's just a figment of your imagination. It's not just food, though! You create a magical replicant of anything you think of--in fact, try it. Think of something. Anything. And now, forget that thought.

And then, remember, with each passing thought, there is a corresponding magical replicant in your brain--and every time you forget something, you are murdering an innocent thought somewhere deep in your mind... That thought you just had? You killed it. You're a murderer.

This also strengthens my theory that Ness is always thinking about eating chicken. That's why chicks make Ness happy and forget his homesickness--he contemplates eating a giant chicken with each passing moment, even to the point that he can forget that he misses his family and home. I don't know what the heck Queen Mary is thinking, though. Maybe she's just loony.

- BB Gang Zombie

The Flying Man represents everything that Ninten and Ness could be if they were not hindered by fear, doubts, etc. He helps Ninten and Ness during their journey because he is to help see their masked potential. When dying, they do not return because Ninten and Ness must see the courage within themselves.

- PKPetalLove