Some on both sides of the debate argue that independence will mean that the Scottish saltire will automatically be removed from the Union Flag.
However, this is not necessarily the case. Despite Irish independence the Irish red cross still is part of the Union Flag, although the reason given for this is the continuation of Northern Ireland in the UK.
There is further complexity because the Union Flag appears on other national flags including Australia and New Zealand.
In the end a state can have whatever flag it likes and it is up to its government so if the rest of the UK government wishes to keep the flag there is nothing Scotland can do about it.