The United States recently shot down a Chinese high-altitude balloon after it apparently travelled from China and flew over Alaska and British Columbia.

Its first public sighting was over Montana where it was seen to “hang out for a longer period of time” over military installations where nuclear missiles are located.

Panic bells sounded, and fighter jets were scrambled as tensions between China and the U.S. intensified due to the incursion of a flying object into American airspace.

Another balloon, also of Chinese origin, was spotted flying over several countries in Latin America.

Balloon versus airships

China has stated it “strongly disapproves of and protests” the downing of what it calls a “civilian airship” with “limited self-steering capability” used “for research, mainly meteorological, purposes.”

However, the U.S. Pentagon noted the object was a “manoeuvrable Chinese surveillance balloon” with a “broad array of capabilities” that forms part of a Chinese fleet of balloons developed to conduct surveillance operations.

Balloons and airships are both considered aircraft under international law. Airships are more manoeuvrable than balloons, which are wind-propelled. Even Chinese regulators define an airship as an “engine-propelled, lighter-than-air, manoeuvrable aircraft.”

The International Civil Aviation Organization (ICAO), the United Nations agency that regulates global civil aviation, describes a balloon as a “non-power-driven, unmanned, lighter-than-air aircraft in free flight,” and says that an airship must give way to balloons precisely because an airship is more manoeuvrable.

The organization’s 1944 Chicago Convention provides that “every state has complete and exclusive sovereignty over the airspace above its territory.” Any aircraft, regardless of whether it is a commercial airliner, balloon or airship, cannot fly over the territory of another country without permission.

Military operations?

If the Chinese balloon was actually a military aircraft or conducting military operations, as many countries and experts believe it is, there is even less of a right to over fly the territory of another country.

Indeed, both the U.S. and Canada openly complained that China’s balloon violated their respective airspaces as well as international law.

Additionally, there are specific international standards regarding the operation of heavy unmanned balloons that suit the description of what flew over Canada and the U.S.

These standards require a country to properly authorize and operate any balloon originating from its territory. The launch and trajectory of any balloon must also be communicated in advance to relevant air traffic services to “minimize hazards to persons, property or other aircraft.”

Furthermore, before the unauthorized entry into the airspace of another country, the operation of the balloon must be terminated. China does not appear to have fulfilled any of these obligations.

To safeguard the safety and security of international civil aviation, the ICAO should further clarify the rights and obligations of nations on the use of civilian balloons and/or airships, and provide guidelines on how to respond when they enter into foreign sovereign airspace.

Men use ropes to secure a U.S. navy boat to a dock in North Myrtle Beach, S.C., after the navy carried out an extensive operation to gather debris from the Chinese spy balloon downed off the coast of South Carolina. (AP Photo/Nell Redmond)

Previous balloon incursions and downings

The U.S. claims “Chinese balloons have previously been spotted over countries across five continents, including in East Asia, South Asia, and Europe.”

Despite repeating the craft is “of civilian nature,” China has said it was a civilian balloon used for meteorological research but has refused to say to which government department or company it belongs.

The manufacturer of the balloon is reportedly a research and design institute affiliated with the Chinese People’s Liberation Army, and China reportedly has a growing interest in using balloon technology for military purposes.

Due to their agility and ability to stay stationary above targets for long periods of time, many countries, including the U.S., Australia and Germany are again using balloons to provide intelligence, surveillance and reconnaissance.

A giant Canadian weather balloon over Finland in September 1998. The 25-storey helium-filled balloon was launched near Saskatoon to measure ozone levels over Canada but drifted away. (AP Photo/LEHTIKUVA-Ari-Matti Ruuska)

There has been a long history of balloons flying into the sovereign airspace of other nations, all of which were met with protest and/or attempts to bring them down.

In 1956, hundreds of balloons released by the U.S. flew over parts of eastern Europe and the Soviet Union, fuelling diplomatic tensions.

In 1995, American balloonists taking part in a race were shot down by Belarus.

In 1998, despite attempts to down it with more than 1,000 rounds of ammunition, a Canadian weather balloon drifted into British, Norwegian, Finnish and Russian airspace.

U.S. was within its rights

In response to a clear and flagrant violation of its sovereignty, the U.S. had a right to bring down the Chinese balloon. Japan, which also experienced balloons flying over Japanese territory in 2020 and 2021, has said it reserves the right to use weapons to “deal with airspace intrusions.”

Even though China has condemned the “abusive use of force towards the civilian airship” by the U.S, in 2019, Chinese state media displayed images of China’s own air force shooting down a balloon that could “endanger [the] security of air defence.”

There are clear international prohibitions against using weapons against civilian aircraft out of “elementary considerations of humanity for the safety and the lives of persons.” Those regulations do not apply to unmanned stray balloons.

To prevent further balloon incidents, all countries should behave in accordance with international law and avoid actions that may exacerbate tensions and strain international relations.