Travis Bickle has a grim view of the world and the people in it. Little is known about his past except that he fought in the Vietnam war. He lives alone. Likes to watch TV and drive in the streets at night. He can't sleep so he entertains himself by watching porn and ruminating about how degraded the life in the city is.
His days are all the same. Each one like the last. Going on and on with no change. Troubled by his thoughts he decides to take up the job of a taxi driver hoping that he'd get to put in long hours that might keep him from wallowing in misery and self pity. And since he is driving through the streets anyway he might as well get paid for it. He's ready to work anytime and anywhere. Even on Jewish holidays.
As he soon discovers however that it was not a very good choice. Travis finds himself surrounded by the scum of the city. The lowlifes and the degenerates, the dopers and the junkies, the sick and the venal. And suddenly he finds that he is living his morbid thoughts. Mostly cleaning off the cum, sometimes blood. He took a job. He became the job.
During the opening of the movie, Travis Bickle is a helpless man. Lacking a purpose in life he drifts off dark corners. He can recognize the depravity both of the city and his own thoughts but he can do nothing to get out. He circles around the same streets and finds himself around the same people whom he has come to hate so much.
A change comes when Travis meets Betsy. A working girl. Thoroughly disciplined and organized, a character completely opposite to Travis'. He manages to summon up the courage of going over and talking to her. After a few scenes she agrees to go to a movie with him.
It seems however that Betsy didn't share Travis's' taste in movies (porn) and she calls off the thing when he takes her to a shady theater. Should Travis have known better? Honestly I don't know. It seemed that Travis had a good sense of right and wrong. Even though he himself was addicted to porn he had an idea that it wasn't right. With Betsy he could have chosen any other movie at any other time and yet he goes in that same place that he didn't even like all that much. It's very hard to understand the reason for his action. Was he trying to test her? Could this have been a practical joke? Just to tease her up?
Maybe what was intended for the viewer was that even though Travis had an inclination to improve himself he was still very much in the same dark corner that we found him in the beginning of the movie. It would take something much stronger than a fling to get him out.
The episode with Betsy leaves him even more distraught than he had been. He makes a few more weak attempts to socialize. When he tries to talk to fellow cab man about his feelings or when he tires to learn more about sport (a pimp he found on the street). But as he learns that people he talks to have nothing to offer him he spins completely out of control. And when his fear of being God's lonely man is realized he decides to do something about it. Problem was all he had were some bad ideas in his head.
One of them was to assassinate the presidential candidate who was touring the city. The other was to rescue a child prostitute, Iris, from the clutches of Sport. He took steps to achieve his goals. He began by imposing some order and discipline into his chaotic world.
He recognized that TV, pills and too much sitting around had made him soft. He decided to get organized by following a strict schedule in which he'd exercise daily, won't watch any TV and won't take any pills. This change in him was remarkable because it was for the first time the story that he saw something to the completion. Previously his attempts at wooing Betsy and making an effort to talk to other people did seem a bit half hearted. But his desire for self betterment was still fuelled by revenge which simply grew stronger with each push up. Not only did Travis tightened his muscles but he also strengthened his resolve to do what he had set out to do.
He managed to achieve 50% of his goals. While the attempt to assassinate the presidential candidate fails he rescues Iris from Sport. And in a twisted ending he becomes a hero in the city. Praised for eradicating the prostitution mafia.
"What's interesting about the story of Travis Bickle?"
The other interesting part about Travis Bickle was that he really was a "walking contradiction" as Betsy said he was. On one had you have this taxi driver who drains his energy in a porn theater and on the other you have a very thoughtful person with sharp observational skills with a capability of reasoning about human behaviour.
Is Travis an aggressive psycho who practices the "You talking to me" routine in front of the mirror? Or is he a kind soul who takes a girl out to lunch trying to understand why she ran away from home to become a 12 year old prostitute?
"Was it the ideal ending for Travis?"
It's really hard to say. There are two different conclusions that can be drawn from the ending:
First, he never recovered from the coma. And his becoming a hero and all the other cheerfulness of the ending was just a dream.
Second, he did recover from coma and he was actually considered as a hero by the people of the city. In that case would he truly be happy? Was he still the God's lonely man? Or did he find self acceptance? Did he become a person like the other people? It looked like it. He seemed to be happy with his colleagues. Didn't need Betsy or his last mission Mohawk anymore.