Austria is a federal republic of nine states, each with its own flag. The strange thing is that most of the flags are duplicates, or nearly so: the flags of Salzburg, Vorarlberg, and Vienna are pretty much identical, as are the flags of Upper Austria and Tyrol.
I understand that there are occasional (near-)duplicates among national flags—for example, Chad and Romania, or Indonesia and Monaco. But these cases are usually accidental, arising from a relatively simple design being adopted independently and in ignorance of the other usage. Salzburg, Vorarlberg, and Vienna don’t border each other, but they’re still close enough that they ought to have been aware of the others’ vexillological preferences, no? So how did they all end up with the same flag?
I don’t have an answer, but FlagsoftheWorld has two flags for each. One, called the civil flag, is what your page shows. The other, called the service flag, are the same red and white bicolors, but also has coats of arms in the middle.
By the way, the red-white bicolor with the white on top is also the Polish flag.
If you follow the link Flags of Austrian states (you did follow the link, right?), you’ll see that the flags have coats of arms, which are all different.
You’ll notice than in every case (except Carinthia) the flag is a simple bicolour, showing the two principal colours, one of them always been white or yellow, in the coat of arms. In heraldic convention, the palette is divided into “metals” (white, yellow) and “colours” (everything else), and in general a colour must always be juxtaposed with a metal, not another colour, and vice versa. (This is to encourage clear patterns; imagine how the US flag would look if the stripes were red and blue, or red and black, and you’ll see why this makes sense.)
So, the flags are simply a bicolour of the principal colour juxtaposed against the principal metal of the coat of arms. In the case of Carinthia, it’s one colour and two metals. I’m guessing the coats of arms are older, the flags are derived from them, and they represent simple livery, for decoration or display in situations where the full coat of arms isn’t necessary or convenient, or where the coat of arms is also displayed. Since there’s a limited palette of colours and metals used in the arms, this involves some duplication.
Think of red, white and blue bunting as used in the US. It could equally be used in France or the UK, couldn’t it, or several other countries? But that’s not a problem.
The flags of several countries of Central America, Honduras, El Salvador, and Nicaragua, all have basically the same design but differ in a central coat of arms or symbol. That’s because they all were once part of the Republic of Central America, along with Guatemala and Costa Rica, whose flags share some of the same elements.
The flags of Venezuela, Colombia, and Ecuador are also very similar because they were all once part of the Republic of Gran Colombia.
In Austria, I’ll take a wild guess. Before confederation, those were all components of the Holy Roman Empire. Several of them were ruled over by a honcho associated with some princely family, and used that common color for their flags. When they all came together into one sovereign state, each one just retained its old traditional flag.
I did, but my question is about the origin of the regular service flags, not the coats of arms, nor the civil flags they emblazon. I’m presuming that the regular service flags were created first, and the civil flags, as the name suggests, were constructed later to give civilians something to fly. Whoever did the latter clearly had the presence of mind to make them distinct.
Interesting theory, though I’m not sure if it applies to all of the states. For example, the modern state of Tyrol does seem to have the same flag as its counterpart, the County of Tyrol, in the Holy Roman Empire. But Carinthia, which under the old monarchies had the same red-on-white flag as Vienna, Salzburg, and Vorarlberg, now uses a yellow-red-white tricolour.
Another bunch that shares most of the flag: any part of Spain (region or town) which used to be part of the Crown of Aragon is likely to include or have as the main motif of a coat or arms or flag “four bars of red on a field of gold”. You mainly know which one you’re looking at by whether there is a colored fringe where the pole would be or not and by whether the bars are wavy or straight, but all of them share the arms which according to legend Charlemagne granted to Wilfred the Hairy.
In all the cases where there is a commonality in the flags and the territories are close or next to each other, look for a common history. It’s as simple as that.
