I am currently booked on DL flight 79 from JFK to LAX later this month, and noticed that it is one of the internationally configured 757's. Does anyone know how often they trade these out for the standard transcon 757's? The reason I ask is that the last two round trips I have taken with Delta, I purposely selected the flights with Biz Elite, only to find that they were switched out on the departure dates. Anyone know how consistently these flights stay with the internationally configured 757? I am looking for the upgrade, and may switch to DL #137 later the same day of travel (as it has more open seats in biz).
Thanks for your help.