Recently I flew with Southwest from BWI airport. During online check in, it provided “Fly By Priority Lane Access” for extra price. Since I was flying on a weekday after work and just in case if traffic is an issue, I purchased the “Fly By Priority Lane Access“.
So on the day I went in to the Southwest terminal and went straight to the online check in counter to print the boarding pass and went straight to the security check point. I did not see any priority lanes and it was the usual TSA security checkpoint and the usual procedures.
So overall there is not much use of “Fly By Priority Lane Access“. Could it be because it was on the weekday ? If you are not checking in any bags and if you are going to do a online check in and are going to get the boarding pass from the online check in counter and head straight to the TSA security check point and I would think “Fly By Priority Lane Access” is not of much use.
It also depends on which airport you are going to board from and if there is any vacation/long weekend holiday rush during that time.