Superman (Comic Books)

The flag of Krypton, Superman's home planet, first appeared in Action Comics #246 (Nov 1958). The Superman Encyclopedia Krypton page describes it as:

A multicolored banner consisting of pale rays of blue, yellow, lavender, white, green, orange, pink, light green, and red radiating outward from a circular center featuring a green and pale blue design suggestive of a body of water all but encircled by lush green land.

There are a total of 10 rays – each color is used only once except for light green which is used for two rays, one on each side of the red.
Ned Smith, 26 February 2005

On the cover of Action Comics 381, Superman is shown sticking a flag pole in the ground of the U.N. Plaza; on it is hoisted a longer, fringeless variant of the parade flag shown in World's Finest 247, blue with the Superman emblem centered on it.

Superman says on the cover art: "No more United Nations! My Superman banner will replace all other flags!" Eleven flag poles are shown in the background, in various states of disarray.
António Martins-Tuválkin, 8 June 2009

It's actually SV — it's the symbol of the Legion of Super-Villains. It appears in that context in this frame from Adventure Comics 355 "The War of the Legions", April 1967. No hiding here — they wanted the Legion of Super Heroes to know who they were up against! I'm not sure if it's the first time it was used but it's the one I remember best.

In the context of the Absolute Power story it may actually be intended as a combination of parts of Superman and Batman's emblems, though, as you say.
David Galan, 14 May 2014

Superman's comics magazine career started in the Action Comics 1 in 1938, and already in that first issue, the relations between America and Europe play their part in the story. Actual war in the first issues however, was of a quite familiar type: Unstable South American countries or small European countries, waging wars that have gone on for years without any developments whatsoever, for no other purpose than to allow the hero to solve the war.

Not long afterwards, however, the real war threats in the Western world began to influence the story. With Superman boldly doing the right thing, the stories tended to show what the creators apparently considered right. In this case, that meant that any peace movement of any kind was unmasked by Superman as a plot either to keep the USA from arming itself or to prepare the invasion of the country by some foreign army.

In one such story, in Superman Comics 10 (from 1941), Lois Lane and Clark Kent are sent by their editor in chief to the Dukalia-American Sports Festival. This festival takes place in the Municipal Stadium, and it's held despite the fact that Dukalia is at unfriendly terms with the USA. The Dukalian consul holds a speech in the stadium in which he claims that Dukalians are superior to any race or nation, and furthermore that this proofs that they are entitled to be the masters of America.

We do not see the USA entering WWII a year early because of this, but we do get to see what appears to be the Dukalian flag: A reddish flag with a white disk in the centre, with an unusual cross shape. That's as far as the authors were willing to go, though I expect few people would have missed the reference to a real world country with a similar flag. The flag of Dukalia has a orthogonal cross spanning the circle, with a second bar approximately the width of a bar above the horizontal bar; wheel cross meets cross of lorraine.

The colour of the field is not bright red, but is a much greyer shade. This is not a colouring issue, as Clark Kent can be seen in the image with the flag as well, and his tie really shows red.

In the flag image, the cross is merely an outline, but on the next page we see the symbol used apart from the flag, and there it has the cross entirely black instead. It may be that the outline was supposed to be filled in with black in the flag image as well. (The green background of the symbol is the surface of the structure it is shown on.)
Peter Hans van den Muijzenberg, 15 February 2013

On the cover of Action Comics 381, Superman is shown sticking a flag pole in the ground of the U.N. Plaza. Eleven flag poles are shown in the background, in various states of disarray.
António Martins-Tuválkin, 8 June 2009

I did approximations of these flags, drawing them all in the 1:2 that the Superman banner appeared to use. (As seen left to right.)

image by Peter Hans van den Muijzenberg, 13 September 2011	Maybe Iran's plain tricolor of 1964-1980. As the comic is from 1969, this would fit. (The second pole from the left; pole slightly bent.)
image by Peter Hans van den Muijzenberg, 13 September 2011	Somewhat along the lines of the United Nations flag. It looks like the actual artwork uses a more conventional projection, and it's hard to see whether there's more to it than the projection lines themselves. it seems to show a green wreath, not white, and the emblem is overall too big. It adequately shows a lighter shade of blue than that on the Superman flag. This lighter shade of blue, very pale, is not the special "U.N. blue" shade, though. Please note that this is not the flag of a fictional entity more or less inspired (the flag and/or the entity) by the real United Nations, but rather an erroneous depiction of the U.N. flag, akin to so many in the real world, just happening to be in a fictional context. (The third pole from the left; flag still hoisted on a straight vertical pole.)
image by António Martins-Tuválkin, 8 June 2009	Then a green and orange horizontal triband; it might be there's supposed to be some charge in the centre. The flag would be slightly before the US in the order they are hoisted in, but no such country flag comes to mind. Of course, the artist may have ignored that order, and the colour artist may also have used paints different from the intended ones. (The seventh pole from the right; pole slightly bent.)
image by Joe McMillan, 6 May 2003	The United States flag is clearly recognisable, though the number of stars is not. It is apparently well depicted, with a dark shade of blue. Counter to the other national flags visible, that had their poles bend or broken, the Stars and Stripes still flies proudly. Superman being from the United States, and all, this one of course remains untouched. Or maybe a US comic wouldn't sell very well if the cover would shown the national flag in distress. (The fifth pole from the right, though the flag is visible furthest to the right; hoisted on a straight vertical pole.)
image by Peter Hans van den Muijzenberg, 13 September 2011	This is a sun flag, like the war flag of Japan. The best approximation, matching the hoist, which is completely visible, results in a rather asymmetrical fly. On the cover, most of the fly is behind the next flag. At the scale and resolution of the cover image, there's a hint that there's a ray just behind the next flag. For that to be possible, the number of rays would have to be larger, at the least in the fly. This one is on the pole next after the one flying the Stars and Stripes. But indeed, no better suggestion than that it's supposed to be the Japanese naval ensign. (The fourth pole from the right; pole crooked downwards almost to the ground.)
image by António Martins-Tuválkin, 8 June 2009 image by Peter Hans van den Muijzenberg, 13 September 2011	Last a yellow flag with just a blue hoist triangle, bearing something that looks a bit like a with white sun or a white lean six-pointed star. Again, these colours may not have been what the graphics artist intended. There's a line running through the middle of the flag, which now shows as a slight fold, but may have been intended to separate the flag into two stripes like, say, the Philippines. (The first pole from the right; pole crooked downwards almost to the ground.)

António Martins-Tuválkin, 8 & 14 June 2009, and Peter Hans van den Muijzenberg, 13 September