Not by any means. It was mainly used by France to distract England in various wars those two were having in return for promises of assisting the Scots, the 'auld alliance'. Over many hundreds of years there were quite a few Scots who went fighting with or alongside the French and lots of diplomatic and cultural interaction. This connection started to die off after Tudor times, primarily because the Scots became staunchly Protestant and thus not well inclined to the French Papists. The merger of the thrones then started the divorce and the Union completed it. However there was still a not insignificant amount of cultural exchange from thereon. And of course there was French assistance (of sorts) during the '15 and '45 Jacobite rebellions.

Apart from that partnership there was no signs that Scotland was a 'major' power, however that is defined.

Actually before the political union of 1707 there was the personal union of 1603.

After the death of Elizabeth I of England the man next in line to the english throne was James V VI (thanks /u/Nairbex) of Scotland. He did ascend to the throne under the name of James I of England. By the way, he is the king that commissioned probably the most famous of the english translations of the Bible, the King James Bible.

So from 1603 to 1707 (with an interregnum in 1648-60, during the Cromwell regime) England and Scotland were governed by the same King or Queen, but were considered two different countries with different laws and governments. That said, the foreign policy of the two kingdoms, being decided by the same person, were obviously closely aligned.

Many Scots served as mercenaries for European countries under agreements; practically the entire clan Mackay was in service for the Dutch Republic. Scotland might not have classified as a major power but it certainly possessed significance in certain key areas.