Ominous Floating Spaceship

"Independence Day. That alien invasion movie. The first part, where the aliens come and they look up between the buildings and the sky is gone and, like, all they see is metal. Just as far as you can see, that steel ship looming up there. I remember thinking that’s what the end of the world will look like. It won’t be wars and tanks or a meteor. It’ll be something we never could have thought of..."

—Jennifer Lopez, John Dies at the End

Some aliens want to make a grand entrance. This trope marks the tendency for fleets of mile-long alien spaceships to ominously hover, several hundred feet over the world's cities without doing very much. It usually means the start of an Alien Invasion but it can be subverted. Expect shots of shadows washing over cities like a tide, awe-stricken people looking upwards and Jittercam footage of the ships over every major city. Five Rounds Rapid against them will be useless while their Wave Motion Gun will be devastating when they decide to use it. Absolutely no Mid-Air Bobbing ever. Quite inexplicable as not only would it expend vast amounts of power and present a big target but by Newton's Third Law, crush everything underneath it. Perhaps it's because Power Floats or because ships float in the sea and Space Is an Ocean, but it also adds to the menace: how can something that big hang in the sky without making a furious amount of engine noise and disruption? Clearly, they must be fearsomely advanced, and the Puny Humans defenses will be nothing to them.

It nearly always occurs Twenty Minutes in The Future by Higher-Tech Species and is never inverted. Probably because humans are too polite.

Examples of Ominous Floating Spaceship include:

Advertising

An advert for Doritos in the UK has a giant chip hovering above London in this manner.

Anime and Manga

The Arume ships in the final episode of Blue Drop.

Films

The alien ships in Independence Day. An interesting bit of Fridge Logic in this one - the ship's center is hovering a teeny bit over the mast of the Empire State Building. That would mean the spaceship was scraping the tops off of the World Trade Center towers.
Briefly seen in the Jittercam news footage at the start of Alien Nation.
Done by the the alien ships in Signs, but they're invisible.
The alien ships in Skyline.
The Mother Ship in Close Encounters of the Third Kind.
The alien Mother Ship in District 9.
The Xilians' Mother Ship in Godzilla: Final Wars..
The ship at the end of The X-Files: Fight The Future does this for a bit.

Literature

Arthur C. Clarke's novel Childhood's End (1953). The Overlords' ships mysteriously appear over the major cities of Earth. Many years all but one disappear, leading to speculation that the rest were illusions the whole time.
- This may just be the Ur Example of the trope.
The Vogon Fleet in The Hitchhiker's Guide to the Galaxy.

Live-Action TV

The Visitors' ships in V, both versions. Likely the Trope Codifier.
The Sycorax asteroid ship in the first Christmas Special of Doctor Who.
Stargate SG-1 does this at least once a season. A few notable instances are:
- Inverted in "Thor's Chariot", where the titular Asgard's flagship Beliskner appears and performs a Gunship Rescue against Heru'ur.
- "Scorched Earth" plays it straight. The entire plot of the episode revolves around convincing the Ominous Floating Spaceship not to terraform a resettled civilization out of existence.
- Anubis's mothership over the capital of Kelowna on Jonas Quinn's homeworld of Langara. Less suspenseful for the viewers, as it is no doubt that Anubis wants to invade, but true for the people of Kelowna, who have never seen a Ha'tak before.
- Inverted in the episode "The Lost City", with the USS Prometheus floating over our heroes. In this case, defending them from Anubis's forces.

Video Games

The Chimera ships in Resistance 2.
Bowser's saucer in Super Mario Galaxy.
Many, many times in the Halo games, mostly Covenant ships but sometimes UNSC ones too.
The Reaper Fleet in Mass Effect 3, particularly unnerving as they actually drop out of the sky, defying Newtonian physics when they land on the ground as gracefully as an insect lands on a leaf. The sight of two kilometer high spaceships casually walking around and laying waste to their surroundings is impressive, to say the least.
- Various allied starships similarly can be seen hovering over various planets, in usually short-lived attempts to fend off the Reaper onslaught.
These are present whenever you go outside in Iji.

Web Original

In the abandoned and incomplete Fenspace Alternates story The South is Rising (Somebody Get a Hammer), the S.V. Grover's Corners -- a Fen spacecraft which is a three-quarter-mile diameter sphere -- is sent to hover directly over the capitol of the Timeline-191 Confederate States of America.

Real Life

Lenticular clouds have been mistaken for this trope and may have inspired it image here
The Phoenix Lights incident is an alleged real life example. On the night of March 13, 1997 thousands of Arizonians, including the governor of Arizona claimed they saw a massive mile-wide UFO fly over the Phoenix Metropolitan Area.