Pilots are trained about a trick: if an object is moving a bit left, right, up, or down in their field of vision, they are safe. If an object hangs in the same spot in their field of vision they are on a direct collision course and must act! The pilot's actions were reasonable under the circumstances. If it really was an airplane he had a fraction of a second to react, not time to ponder what it might be.
This field of vision trick works in many circumstances. When landing, the spot lined up on the windshield that is neither rising or falling is the spot the aircraft will touch down. If the top of a mountain range is slowly moving down it means the airplane will clear it. A sailor can also tell if two boats are on a collision course by this same field of vision effect.
Mariners know all about that same trick. When I said Venus doesn’t move that fast, I was talking about its track through the ecliptic. If it was a morning star rising 90 minutes before the sun three weeks ago (for example), its status is not that different now. The point being that those who fly regularly you’d think would have the general whereabouts of these things in the backs of their minds. Perhaps the presence of other traffic near by, combined with the grogginess of sleep, overrode this.