Originally Posted by rajvar
When are seats sold but not assigned? I'm just looking at 3/24 NRT-JFK UA800 which EF says is Y0..., but looking at the seatmap, it's wide open. In what cases are seats just not assigned to people who book? Seems odd that the vast majority don't have a seat?
On the note of Y0... is this flight oftentimes oversold?
Don't know when this occurs, but it's very common to see a large number of unassigned seats on a sold-out flight. Maybe it's pax who don't bother to do seat assignments through their travel agent (or Orbitz, Expedia, etc.) and they aren't automatically given seat assignments. Since I always pick my seats (carefully, of course!

), I don't know how often you can end up without seat assignments if you skip that step.
As for the Y0, I believe that flight is frequently oversold, as are many transpacs. For example UA800 on 3/26 is F0 C0 Y0. However, I just checked and the 3/24 flight is showing Y5 right now, so it looks like a few seats opened up.