In the United States militia movement, black helicopter is a symbol of an alleged conspiratorial military takeover of the United States, though it has also been associated with UFOs, men in black, and similar conspiracies. Rumors circulated that, for instance, the United Nations patrolled the US with unmarked black helicopters, or that federal agents used black helicopters to enforce wildlife laws.
Stories of black helicopters first appeared in the 1970s, and were linked to reports of cattle mutilation. It is possible that the idea originated in Hal Lindsey's book The Late, Great Planet Earth, published in 1970 and popular among conspiracy theorists. Lindsey theorized that the locust-like creatures referenced in the Book of Revelation in the New Testament were actually helicopters, which John had never seen and thus did not know how to describe.
Media attention to black helicopters increased in February 1995, when first-term Republican northern Idaho Representative Helen Chenoweth charged that armed federal agents were landing black helicopters on Idaho ranchers' property to enforce the Endangered Species Act. "I have never seen them," Chenoweth said in an interview in The New York Times. "But enough people in my district have become concerned that I can't just ignore it. We do have some proof."
Believers in UFO conspiracy theories often claim unmarked black helicopters are seen in the vicinity of UFO sightings, the theory being that the choppers belong to an alleged secretive government department who cover up evidence of alien visits and UFOs from the general public.
The black helicopters theory resonates well with the belief held by some in the militia movement that troops from the United Nations might invade the United States. The John Birch Society published an article in The New American detailing how the existence of the covert aircraft was mostly the product of possible visual errors and a tendency towards overabundant caution.
The following organizations and government agencies are known to operate black and/or unmarked helicopters in the United States for unclassified uses:
- U.S. Customs and Border Protection operates a dozen black-and-gold UH-60 Black Hawk helicopters.
- The U.S. Army's 160th Special Operations Aviation Regiment use helicopters primarily painted black and other US Forces operate helicopters painted in black or dark colors, particularly the Pave Low, which was optimized for long-range stealthy insertion and extraction of personnel, including combat search and rescue. The U.S. Army regularly conducts both exercises and operational missions in American airspace. Some of these exercises have taken place in densely populated cities, including Los Angeles, New York, Detroit, San Francisco, New Orleans, Oakland, Chicago, and Washington, D.C. Most operational missions are tasked in narcotics interdiction in the American Southwest and out of Florida and Puerto Rico. By extensive use of IR, radar, GPS and night vision devices, as well as other classified means, they are able to fly in zero visibility conditions with no running lights. Frequent practice results in frequent sightings by concerned members of the public.
- In the early 1970s, the CIA conducted test flights of two black Hughes 500P helicopters  at Culver City, California. After the mission assigned to it had been completed, one helicopter was transferred to the ownership of the Pacific Corporation of Washington, D.C. The second helicopter currently flies for the Snohomish County Sheriff's Office in Washington State.
- Many defense contractors and helicopter manufacturers also conduct public flight testing of aircraft and components or fly aircraft in public view to test ranges or other corporate airfields for training or demonstrations. Occasionally, some of these aircraft will be made for military clients and are painted in black or dark colors.
- Many US law enforcement agencies use black helicopters for surveillance, transportation, and patrol. Some of the agencies that use them are U.S. Customs and Border Protection, Immigration and Customs Enforcement, the U.S. Marshals Service, the Drug Enforcement Administration, and the Federal Bureau of Investigation.
The term has also been used to ridicule other conspiracy theories or conspiracy theorists. For instance, a Slate article on basketball refereeing, said: "In the wake of this scandal, every game will be in question, and not only by fans disposed to seeing black helicopters outside the arena." Vice President Joe Biden had recourse to the term in a speech responding to the National Rifle Association during the 2013 White House campaign for background checks on all gun purchasers, saying, "The black helicopter crowd is really upset. It's kind of scary, man." When the Department of Homeland Security (DHS) proposed a database to monitor the activities of journalists, bloggers and other “media influencers,” and some people raised concerns, DHS's spokesman said, "Despite what some reporters may suggest, this is nothing more than the standard practice of monitoring current events in the media. Any suggestion otherwise is fit for tin foil hat wearing, black helicopter conspiracy theorists."
- Blue Thunder; a film where a police officer is assigned as the test pilot of an advanced, dark colored armed helicopter intended for anti-terrorism duties. He then discovers a conspiracy to stir up riots in urban ghettos as a pretext for declaring a national emergency in order to establish a dictatorship, using such helicopters to subdue the population.
- Airwolf; a television series where an intelligence agency known only as 'The Firm' uses an advanced dark colored armed helicopter to conduct espionage missions both abroad and within the United States.
- Amerika; a television miniseries in which the Soviet Union has taken over the United States under the pretext of the United Nations and uses black painted armed helicopters to destroy all resistance to their rule.
- The X-Files:Fight the Future is a 1998 feature film written by Chris Carter and Frank Spotnitz. Black Helicopters feature when they chase the central characters Fox Mulder and Dana Scully who have discovered a storage facility for honey bees which have been genetically engineered to carry an extra-terrestrial virus.
- Black Helicopters is a novella written by Irish-American author Caitlín R. Kiernan. The chapbook was published in 2013 by Subterannean Press to accompany the hardcover first edition of Kiernan’s story collection The Ape’s Wife and Other Stories. The novella received a World Fantasy Award nomination that year. In 2018, Kiernan followed up the 2013 publication with a revised, definitive edition of Black Helicopters published as a trade paperback by Tom Doherty Associates.
- Weird Al Yankovic mentions "black helicopters coming 'cross the border" in his song "Foil", a parody of Lorde's song "Royals", which starts as an advertisement for aluminum foil and devolves into a conspiracy rant.
- Austin, Jon (29 December 2016). "UFO MYSTERY: Fifteen black helicopters seen 'flying towards location of bizarre sighting'". Daily Express. London. Retrieved 17 July 2018.
- A culture of conspiracy: apocalyptic visions in contemporary America
- The Phenomena Department - Paranormal Events
- Hal Lindsey, The Father of Apocalyptic Christian Zionism Archived January 26, 2012, at the Wayback Machine
- Priorities - May/June 1996 - Sierra Magazine - Sierra Club
- The Paranoid and the Paramilitary Archived April 18, 2007, at the Wayback Machine
- Hastert Leads Congressional Delegation On Border Tour - Jamd at www.viewimages.com
- "U.S. Special Forces behind last month's training in New Orleans, military confirms". nola.com. The Times-Picayune. Retrieved 17 April 2012.
- "Blackhawks Circle Low Through Chicago Skies as Secret Service Releases Security Details". Fox News Releases. WFLD. Archived from the original on April 19, 2012. Retrieved 17 April 2012.
- Air America's Black Helicopter | Military Aviation | Air & Space Magazine
- Air America's Black Helicopter | Military Aviation | Air & Space Magazine
- Smith, Oli (5 February 2018). "Super Bowl terror fears: Black Hawk helicopters SPOTTED over stadium amid FBI presence". Express. Retrieved 16 July 2018.
- "The FBI is Home to Some of the Baddest Special Ops Aviators Around". The Tactical Air Network. 23 November 2015. Retrieved 16 July 2018.
- If the Ref Did It, Here's How It Happened, Slate, July 23, 2007 Archived October 1, 2007, at the Wayback Machine
- Trotter, J.K. (April 9, 2013). "Biden Directly Confronts NRA and 'Black Helicopter Crowd' as Gun Deal Looms". The Wire.
- Staff, Sun Times (April 7, 2018). "Homeland Security to compile database of journalists and 'media influencers'". Chicago Sun-Times.
Media related to black helicopters at Wikimedia Commons