This topic has been greatly discussed. At one point, I saw an article saying that Orthodox Rabbis didn't see a problem with the airport scanners. However, when searching, I can no longer find it.
Now that the ice has been broken by the two modest muslim women travelers, it is time for Jewish travelers to step back and ALSO object to these privacy invaders. There must be another way to provide enhanced flight security, and these machines are not the way.
Muslim women who refused to take 'naked' full-body scan are barred from flight: Manchester to Pakistan
One of the women refused to go through the full-body scanner at Manchester Airport on religious grounds while her companion also declined for 'medical reasons'. The women were travelling together to Islamabad when they were selected to pass through the controversial security screen after checking-in at Terminal Two at the airport.
European rabbis up in arms over body scanners
Body scanners can store, send images
Pope criticizes body scanner. Quote: "Every action, it is above all essential to protect and value the human person in their integrity". "For you this reality represents an ever more task of complex organization and it is a labour that if often discreet and barely known, not always noted but which does not escape the eyes of God, who sees all of Man's works even those that are hidden."
Also articles here Yeshiva World