The next thing in the script is when Travis takes Betsy to the porno movie. This section plays almost unchanged except for a few lines of dialogue. In the script, Betsy says, "But this is a porno movie." In the movie, she says, "But this is a dirty movie." I think this is an important distinction. Betsy is a good girl and she won't even use the word "porno" let alone watch one.
The other dialogue change is when she comes out and wants to leave. She says, "If you just wanted to fuck, why didn't you come right out and say it?" Shepherd's line is, "That was about as exciting as saying, 'let's fuck'." It's neater and cleaner and has a little more subtext. I think she also played Betsy much angrier than Schrader wrote her.
The last change in this scene comes at the end. In the script, she accepts the record, says, "All right, I'll accept the record," and calls for a taxi. In the movie, she calls for a taxi and takes the record from Travis through the window after she gets in, saying, "Great. Now I have two." Again, this is a small, but important change. In the movie she couldn't wait to get away from Travis. In the script, she stays to exchange a few words and tries to explain.
Here's another divergence in the time line. Schrader shows us Travis in his apartment and his diary tells us, "The days move along with regularity…" Scorsese chose to continue with the Betsy story and showed us this scene a little later. But Schrader added all the details right here: the bread and milk with alcohol, the new poster that says, "One of these days I'm gonna get organezizied," and watching Charles Palantine on TV.
Scorsese continued the Betsy story and didn't give Travis a chance to reflect on anything. And when Travis did return to Betsy, Schrader had him wait for her in the street one day. Scorsese went straight to phoning her, the tracking shot of the rotting flowers (Schrader even called for a tracking shot in the script), and the diary entry about the headaches and stomach cancer and only being as healthy as you feel.
At this point Scorsese followed the script and had Travis barge into the campaign headquarters. The difference is that Schrader played the drama out without dialogue. Scorsese stuck in the line where Travis tells Betsy she's going to die in hell. I love it when my ex-boyfriends tell me that.
Schrader wrote that Travis tells his diary, "…how much she is like the others, so cold and distant. Many people are like that. They're like a union." Scorsese substituted "women" for "people." A lot of Travis' problems come from the fact that he can't relate to women at all. He at least manages some sort of human connection with Wizard, Doughboy, and the other cabbies, but women are a mystery to him, and it hurts.
Then we come to the famous scene with the psychotic husband. Schrader stuck in a little bit with some other guy getting in the cab and Travis turning on his "Off Duty" sign, but Scorsese cut that. It confuses the story. Schrader's passenger just tells Travis to pull to the curb, which Travis does. Scorsese embellished the guy with a long tirade to Travis about doing what he's paying for. Schrader describes Travis as watching the woman in the window with, "…the same glazed-over stare we saw in his eyes as he watched the porno movie." I didn't get that at all. To me, Travis looked scared and nervous…
…which is why the next scene leads to Easy Andy and buying the guns. Scorsese stuck in a little bit where Travis meets the other cabbies, to remind us that Doughboy had offered to get Travis a piece before.
Easy Andy emerged pretty much as Schrader wrote him, but part of the dialogue was about Travis being a vet and if there was a firing range around. There was more conversation between the two men in the script, but in the movie Easy Andy just talked non-stop while Travis looked at the guns. Andy's patter is pretty much the same. At the end in the script he says he can get Travis tickets to a Knicks or Mets game. In the movie he says he can get grass, hash, crystal meth, or a brand new Cadillac with the pink slip. Scorsese made him more sinister.
After this, Travis gets in shape and puts his arm through a gas flame. Scorsese filmed it exactly as Schrader wrote it.
In the movie we get to see Travis talk to the Secret Service Agent at the Palantine rally, but Schrader saves that for later. Scorsese also inserted the "you talkin' to me?" scene here, right after the rally. Schrader also saves that for later.
Scorsese also put the killing of the robber in here, before the American Bandstand scene.
The next thing Schrader shows us is Travis watching ROCK TIME with teenagers dancing. Scorsese left this scene until later, after Travis kills the stick-up man, and got a clip from American Bandstand. It's the scene where the cameraman focuses close in on a pair of platform shoes on the dance floor.
Now Schrader introduces Iris. She jumps in and demands that Travis get her out of there, but Sport leans into the cab and tells her to get out. Schrader's Iris gives up and lets herself be taken away. Scorsese and Foster's Iris puts up more of a fight until Sport says, "Bitch, be cool." That's not in the script. The crumpled $20 bill is, and keeps finding its way out of Travis' pocket until he finally gives it back to the timekeeper (Finger Man).
Travis goes to the movies (more porno, the only kind he watches) and as he's watching in the dark, he starts to think about killing Charles Palantine. In the script his fantasy is much more overt and deliberate. Scorsese cut out all the diary entries that make it obvious and concentrates on Travis' isolation. In the movie Travis seems more impulsive when he first starts stalking Palantine.
Now Schrader shows us the montage of shots where Travis prepares all his weapons. He cuts crosses in the bullets, turns his drawer slide into a sleeve slide for the small gun, and practices getting his knife out quickly. He has also turned one wall of his apartment into a mosaic of Palantine articles and bumper stickers. Travis tells his diary, "Listen you screwheads: here is a man who wouldn't take it any more, a man who stood up against the scum, the cunts, the dogs, the filth."
Scorsese included all of this except the Palantine wall and added the "you talkin' to me?" scene.