I've never flown kilted but I do recall some threads about it. Pack sgian and pin in your check in luggage lest they be confiscated. If you travel frequently you might consider a contemperary kilt with pockets and plastic buckles. Explosive sniffing devices shouldn't be a problem even without a kilt pin, as I understand it it's just a small puff of air out of the less than barely enough to ruffle your pleats.