*Treasure Planet* is Disney's take on Robert Louis Stevenson's classic pirate story *Treasure Island* now reimagined as a space fantasy. Most of the characters, settings, and plot beats are there, just with a spacey-pirate theme.

I believe this flag seen throughout the film is the jack of some kind of Imperial navy that spans much or all of the galaxy. The film has a sequel in the form of a computer game (which oddly enough was released a few weeks before the movie) called *Treasure Planet: Battle at Procyon.* The game identifies it as the **Terran Empire**, though this is never mentioned in the film. Personally, I'm choosing to consider that bit of information extracanonical.

The flag is a field of white with red stripes fimbriated with light blue. A few stars dot the negative space and a heraldic seal of some kind is superimposed at the crossing of the stripes. One might blazon it as follows (thanks to u/[Slight-Brush](https://www.reddit.com/user/Slight-Brush/) for the help):

***Per chevron inverted azure and argent; in chief a compass rose and in base a mullet of eight between four mullets of four points or. for a crest a crescent dependent or.***

Strictly speaking, this "coat of arms" breaks a number of heraldic conventions (such as the Rule of Tincture with those gold mullets on white), but I'm willing to let a fantasy empire from either an alternate universe for the far-flung future bend the rules a bit.

The flag gives a vaguely British and/or European, seemingly having taken inspiration from a number of sources, with an added cosmic flair.

We first see the flag (or a very similar variant) pinned to the wall in Jim Hawkins' childhood bedroom. The smaller details change from shot to shot, but I was able to determine a nearly perfect hoist to fly ratio of 2:3. Later on, we see it waving atop the mast of the RLS Legacy (a name change from the original books' *Hispaniola*, now cheekily paying homage to the author's initials). When John Silver initiates a mutiny, he orders this flag to be changed for the Jolly Roger.

  
Note: Other sources I've seen online show this imperial flag looking rather different-- the stripes especially going in all the wrong angles. I'm confident that my reconstruction is much more accurate to what we see on screen.

Imperial Ensign seen aboard the RLS Legacy (Treasure Planet)