V (tv)

This is the flag of the invading aliens ("visitors") from the US TV-series V. This new image was made after reviewing an old taped episode — the series was even worse than I recalled, and the book sucks! The flag is a Nazi-like red cloth with a white disc and on it, in red, the symbol of the "visitors". It was extensively used in the film, especially as long vertical hung banners.
António Martins, 7 July 1999

The background is supposed to be orange red the disc is white the center symbols were black, symbol was used on flags banners and on armbands in the series. Never in the red as shown.
F. Prohaska, 9 January 2000

Regarding the actual color of the visitors' flag, I tried to gather evidence in favour of any of the mentioned designs but I found nothing really "authoritative" in the web:

Flag image on the costumecostumecostume.com website. Doesn't seem to be a "real" flag (i.e., as those used in the series). Plain red cloth with the visitor's emblem very in black, filing the whole flag.
Still shot from Wikipedia: Dark orange flag (?) with black symbol, no disc.
Another still also from Wikipedia: red logo on white, in vehicle livery.
On cafepress.com you can find Visitors' mugs, tees & clocks but no flags. They carry emblems that are red on white, red on black or black on red.
The thevisitors.net fan's website logo showed red emblem on black disc (on white background?). [alternative] The only mention to flags in the whole site seem to have been inconclusive regarding the flag design.
From an episode transcript:
Donovan:I shot her. I know I didn't miss.
Ham: Those little red suits are bulletproof, remember?
Another transcript mention only "a podium and table, flag staffs bearing both Visitor and Science Frontiers colors."

António Martins-Tuválkin, 13 September 2005

There's another possible source of information — but it's no more authoritative than those you have already found. Science fiction TV programmes and films often get made into computer games. Depending on who made them, whether they cared about the original, what technical and financial constraints they were under etc. etc., you may or may not get a faithful reflection of the original.

My old 8-bit computer, the Amstrad CPC, had a version of V, and I have just downloaded it from the web and run it in an emulator on the PC. Here, in all its 8-bit glory, is the symbol which appears on the walls of the running, jumping, shooting maze game.
André Coutanche, 13 September 2005

Visitors