G.I. Joe will be replaced with Batman beginning Apr 29 :(
I am not sure which it'll be but it might be Batman Beyond or Batman: The Animated Series..

Why is G.I. Joe leaveing The Cartoon Network line up
as of April 29 ,2003 did G.I. Joe contract expired with
The Cartoon Network.


Take Care and God Bless
Aaron

I'm not sure if it expired. Ever since they began airing it last summer, it's been on hiatus a couple times. Probably one of the many toons on CN that has been on hiatus over 5x or more has to be "Thunder Cats"..