Re: what are scales for traditional scottisch folk music ??
Much folk music, especially Irish and Scottish, uses scales that predate the modern "major" or "minor" tuning system, using instead the older modal system (think white keys on the piano often with different starting or ending notes other than "C" - the traditional major scale). As traditional folk instruments are often diatonic instead of chromatic (for example: traditional bagpipes and mountain dulcimer) they lend themselves quite well to the use of modes. Two of the more common ones for Irish/Scottish music are Mixolydian Mode (think major scale with a flatted 7th, starting and ending on G), and Aeolian (natural minor, starting and ending on A).
For your specific question, after doing a bit of checking, the bore of the bagpipe's chanter is described as having a major scale with a flatted seventh, with the result that most bagpipe tunes are written in Mixolydian Mode.