does the x-men appear uin one episode?
Yes, some of the X-Men (wearing civillian clothes) do make a cameo in one of the FF episodes.Ben Grimm forever!
And in the episode Doomsday, you get to see the Black Bird, briefly.
Is the Black Bird an aircraft?Ben Grimm forever!
Yeah, it's the big blue jet you see the X-men fly in in the movies. Don't ask me why it's blue and they call it a black bird.