Is AOP a type of decorator pattern?

I would say AOP (Aspect Oriented Programming) is NOT a pattern by itself (and thus not a type of decorator pattern from my POV)... its implementation can be done via one or more patterns (including the use of decorator pattern)... AOP is a programming paradigm IMHO - other paradigms are for example OOP, functional programming or procedural programming...

I agree with Yahia in general. Note that while aspects add and possibly modify existing functionality, they are usually applied to whole methods or classes, not single instances.