i can see by the number of stars certain planes are supposed to maneuver better, fly faster, and have more or bigger guns. is there a difference in the roll rate as well? or do they all roll the same? same with climb and dive...is that enhanced in the "maneuver" rating?

Overall. All the manoeuvring capabilities improve with additional stars.

The only thing that really affects how well your plane flies and turns is its speed. Even if you had 1 star in agility and 5 stars in speed you would have a awesome plane. The plane would just have a wider turning radius but would turn around just as fast as anyone in any other plane with 5 stars of speed.