Originally Posted by
alggag
On Southwest it generally does mean same plane, or at least they were planning to use the same plane. WN typically only subs another aircraft in the way that the OP describes if the original plane is running behind schedule.
On the other hand, legacies run scheduled "same flight number different plane" direct flights all the time which is something that I personally think is a bit of a shady practice.
I agree with the fist paragraph. Unlike other carriers, southwest doesnt have the traditional route/spoke system where they have a ton of planes to flip around at a hub. If there are significant east coast delays they substitute another plane to do the west coast route of the flight.
I disagree on the second part....I would prefer airlines locked the same number on routes irrelevent of planes they used. It makes it easier to track airline long term behavior of routes.
Southwest is known to regualarly change route numbers which makes it alot much harder to track on time performance stats from year to year.