Seems curiously low power for a Phantom Monster / Stronghold Zeppelin variant.

Also, it's kinda odd to see a creature with flying also say "can be blocked only by creatures with flying". That's what flying means. Except that it actually excludes creatures with reach. But that's a pretty strange subset of potential blockers to want to exclude.

What - green ones?

Blue is allowed to hate on green, this is "Fly higher" kinda, and seems like a simple enough take on it.

It's a confusing / unclear take on it, though. It'd be much better to just say "can't be blocked by green creatures". (At that point this is close to Treetop Sentinel, and its size makes a bit more sense, I guess.)

I had missed Treetop Sentinel I'll change it to read can only block creatures with flying.

I had missed Treetop Sentinel I'll change it to read can only block creatures with flying.