I was on a trip to Scotland recently and I went, of course, kilted. I have read about several here on the forum who have had bad experience with the security check at the airport. My kilt has 3 large buckles and on the way to Scotland the metal detector went off like crazy, and I got the full treatment.
On the way home from Scotland I had the best advice ever from one of the guards at the security checkpoint. He said I had to turn the kilt 90 degrees so that I had the buckles on my stomach and in the back. In fact, this worked perfectly and I could go on without being "molested" .
So remember this trick next time you're out flying.
Skål!