Who were those two old guys?

Those Two Old Guys

Those two old guys featured in The Iron Giant and The Incredibles were Ollie Johnston and Frank Thomas.
Brad Bird honored these two because they inspired him and were part of Disney's Nine Old Men, whom he looked up to. In their cameo in the incredibles the dialogue between Frank and Ollie goes something like this:
Frank: Hey you see that?
Ollie: Yea
Frank: that's the way to do it, its oldschool
Ollie: Yea there's no school like the oldschool.
Then one of them laughs.

In Lady and The Tramp, Frank Thomas was the animator who did the spaghetti scene with Lady and Tramp though it was Ollie who animated Lady for most of the movie.