See details page for summary of Orbital.

Note, orbital is deliberately costs more than flying, cheap fliers are replaced by hover.

In general, I'd prefer to avoid "target player's library" since it can leave people unsure whether to use it on themselves or the opponent, and manipulating opponent's libraries can be really frustrating if it happens repeatedly, but I remember hearing that most of the time people use it on themselves, and only on the opponent when they have a specific reason.