The Dissent is more in line with previous 4th Amendment cases and contains a discussion regarding the original subject of this thread. Even the dissent in Sitz would likely agree that security checkpoints in airports are constitutional - if there was a proper protocol in place that eliminates arbitrary decisions by the screeners.
In this case, any screen of a female should be done in private by two female screeners and the subject of the screening should be allowed to have her husband/family member accompany her into the private area. I'm not sure how to handle a female traveling alone.