Although Scottish Baronies are normally transferred only with their land, a group of titles were connected to the Heir Apparent by an act of parliament and they followed the Stewart line down to HRH The Prince of Wales, who is today the Baron of Kyle.
From Burkes Peerage and Gentry entry for the Prince of Wales:
“Scottish titles (Dukedom of Rothesay, Earldom of Carrick, Barony of Renfrew, Lordship of the Isles and Great Stewardship of Scotland) held by the Heir Apparent: These titles are held under the terms of an Act of the Scottish Parliament of 27 Nov 1469 by the first-born ‘Prince' (interpreted as meaning son, even though the word ‘Prince' then could apply to either sex) of the Kings (to be interpreted as including Queens) of Scots. Since the union of English and Scottish Crowns in 1603 (more precisely the death in 1613 of HENRY PRINCE OF WALES, CHARLES I's elder brother) the limitation of the Scottish titles of the Heir Apparent has been treated as identical to that of the Dukedom of Cornwall. The Dukedom of Rothesay was first conferred in 1398 on DAVID STEWART, first-born son and Heir Apparent of ROBERT III KING OF SCOTS. On DAVID's dying without issue in his father's lifetime the titles reverted to the Crown. His younger brother JAMES was granted in 1404 the entire parcel of territory which went with the post of Steward of Scotland and since this included Rothesay, the lands that appertained to the Earldom of Carrick and the (then presumably territorial) Barony of Renfrew and since at that time such honours were inextricably bound up with the holding of land rather than personal to the title-holder, as is nowadays the case, he is deemed to have become Duke of Rothesay, Earl of Carrick and Baron Renfrew, also Lord of Kyle (though this last honour does not now feature in the recital of the Heir Apparent's dignities). When JAMES succeeded as JAMES I his peerages merged in the Crown.”
Also see The Complete Peerage Vol. XI – 14 page 209 entry under Rothesay for “Baroniam de Kyle."
Many thanks to Robert Noel, Lancaster Herald of the College of Arms for his kind assistance in research.
In Scotland, HRH is known as the Duke of Rothesay and below is that standard
His standard in Wales
His Standard as the Duke of Cornwall
There are records of two other Barons of Kyle; the Barony of Kylesmuir and the Barony of Kylestewart.
Kylesmure is recorded as a regality (probably spelling variant of Kylesmuir) as is the regality of Kyle-Regis.