Airspace used by commercial jetliners is generally considered restricted but public (not private) space. It is not a stretch to consider flight paths as public roads in the sky. Travel on public roads on the ground come with certain restrictions. We see below how searches and seizures are handled where traveling on such roads in a vehicle are concerned.
The government may not detain an individual even momentarily without reasonable and articulable suspicion, with a few exceptions.
Where society's need is great and no other effective means of meeting the need is available, and intrusion on people's privacy is minimal, checkpoints toward that end may briefly detain motorists.
Consider the airport scanners and "pat-down" procedures in light of the limitations placed upon law-enforcement where vehicular searches and checkpoints are concerned. Note the words, "intrusion on people's privacy is minimal." How minimal is the intrusion on one's privacy where the full-body, naked scanners and hands-inside-pants pat-downs are concerned? They are highly intrusive. They are about as intrusive as they can be, short of cavity searches. The scanners are used to examine at extreme high-resolution rates one's "private" parts, one's nakedness. For a Biblically religious person, uncovering another's nakedness is a very serious matter with heavy spiritual consequences if done for the wrong reason and in the wrong way.
Also very important concerning these scanners and pat-downs though is that there are "other effective means of meeting the [perceived] need." Law-abiding citizens are known as such by the government. They are all to be presumed innocent.
The effective means though is to solve the underlying reason for any "threats" in the first place. Address the root-causes. Address the grievances of those who it is claimed seek to do harm to the American people and their property, private and public.
The government of the U.S. has not attempted to do that because the government is unwilling to curtail it's evil-Empire building. That's the main problem.
The solution is for those in government to change their minds and hearts or if they are unwilling to do that, for the people to replace them with those who are ready, willing, and able to get at the root causes and fairly and openly to address legitimate grievances and end evil-Empire building, including false-flag attacks and the like.