As per Soutwest's website...they will continue to operate independently until they receive their single operator certificate next year. Then, they will slowly start to integrate.
I don't think you will see flights already booked change. Eventually they will stop putting out new AirTran schedules. Since they operate so differently, it would be difficult to do codeshares the way Delta/Northwest and United/Continental did.
I thought same thing, booked seats/paid already so was kinda worried, but I went to the site they linked on the email and it said what the other pp's said, no changes, nothing to worry about, keeping fingers crossed !
I don't think you will see flights already booked change. Eventually they will stop putting out new AirTran schedules. Since they operate so differently, it would be difficult to do codeshares the way Delta/Northwest and United/Continental did.
Assigned seats and baggage fees shouldn't be an issue with codeshares. Southwest credits can now only be used by the original passenger. I don't think change fees is an issue with codeshares.