Very vaguely, that is.
Just look at it:
The featureless head of the plane reminds me of that episode of Are You Afraid of the Dark where the kids discover their neighbors were aliens and had no face–just smooth, uninterrupted skin all around.
And that upside-down V tail just looks so wrong and adds to the offness.
Of course, there’s also the whole matter of them being silent watchers from the sky armed with missiles…