How does Aldrick change over the course of the book? What are some examples showing his change?
Aldrick changes quite a bit over the course of the book, both in terms of politics and in how he relates to others:
The dragon: Aldrick comes to realize that adopting the alter-ego of the dragon for a few days during carnival is not self-fulfilling or productive. The story necessarily calls into question if all the time and energy spent on the costume and the quasi-religious attitude Aldrick has towards the dragon is warranted.
Being a warrior: Aldrick's experience with Fisheye in stealing the police vehicle changed the way he understood the people on the Hill and their nature as a colonized people. While Aldrick definitely connects with others through their shared oppression and poverty, his failure to get people to rise up during the two days they drive around the city in the van suggests that there is something flawed about his politics of resistance.
Sylvia: Aldrick's commitment to the dragon prevents him from forming a relationship with Sylvia, or intervening in her life in a meaningful way. When he gets out of prison, Sylvia has already "sold" herself to Guy in exchange for a stable life.
Each of these examples show that Aldrick over the course of the book realizes that his fixation on the dragon came at the expense of truly understanding the plight of the people on the Hill or what sort of action can truly help them best.
In my opinion, the changes in Aldrick Prospect amount to a sad, sad story. He changes from a loyal rebel into an isolated and misguided criminal.
The tradition of the Trinidad Carnival has always been particularly important for Aldrick. He takes great pride in one thing: designing his costume for the dragon int he parade. This loyalty to Trinidad is his beautiful rebellion against the oppression in his society. It has always stood in the way of him having a "real" job. In Aldrick's mind, it connects him to the ancients of Africa.
Unfortunately, this loyalty becomes extreme and misguided, eventually landing Aldrick in jail. The dragon costume becomes SO important, he can't find love with Sylvia. The guilt from this drives him further into isolation, rejecting the rest of his neighbors and betraying his very best friend. This eventually dives him even away from his community importance as the dragon. In a sort of misunderstood stupor, Aldrick steals a police car and is imprisoned for five years.
Here is another change: after he is let out of prison, Aldrick realizes his mistake and seeks out his love, Sylvia. Sylvia is engaged to be married to someone else (Guy). The end of the story still ends in despair and depression for Aldrick as he runs from the Hill.