There's a high altitude balloon in the news recently. It seems to have come from the pacific, passed over Canada and now the US. I don't have any official tracking data but a notional trajectory is shown in screenshots below. The graphic is labeled conservatively:

Potential trajectory: suspected spy balloon

Question: Balloons certainly have a place in the history of warfare and intelligence gathering, but these days are there really noted, plausible modern instances of spy balloonery? And are investigative balloons (spy or otherwise) of this size really maneuverable?

screenshots from CNN's February 4, 2023 See path the suspected spy balloon may have taken showing a "potential trajectory" of a "suspected spy balloon" and some high resolution photos showing the balloon and an array of panels that seem likely to be for solar power.

Screenshot from the April 30, 2020 NASA Wallops video B-Line to Space: The Scientific Balloon Story showing the payload and its solar panels. I don't know which balloon mission this is, but we can see images of another similar one in Space SE's What cosmic ray sensor is attached to this Balloon?

From the video:

NASA’s Wallops Flight Facility in Virginia manages the agency’s Scientific Balloon Program with 10 to 15 flights each year from launch sites worldwide. Northrop Grumman, which operates NASA’s Columbia Scientific Balloon Facility (CSBF) in Texas, provides mission planning, engineering services and field operations for the program. The CSBF team has launched more than 1,700 scientific balloons in the over 35 years of operation.

There's a high altitude balloon in the news recently. It seems to have come from the Pacific, passed over Canada and is now over the US. I don't have any official tracking data but notional trajectories are shown in screenshots below. The CNN graphic is labeled conservatively:

Potential trajectory: suspected spy balloon

Question: Balloons certainly have a place in the history of warfare and intelligence gathering, but these days are there really noted, plausible modern instances of spy balloonery? And are investigative balloons (spy or otherwise) of this size really maneuverable?

screenshots from CNN's February 4, 2023 See path the suspected spy balloon may have taken showing a "potential trajectory" of a "suspected spy balloon" and some high resolution photos showing the balloon and an array of panels that seem likely to be for solar power.

A different hypothetical map from Sky News's February 4, 2023 Spy balloon: China wanted 'to be noticed' says Professor Michael Clarke showing a trajectory for an object at 40,000 feet ending up in Montana

Screenshot from the April 30, 2020 NASA Wallops video B-Line to Space: The Scientific Balloon Story showing the payload and its solar panels. I don't know which balloon mission this is, but we can see images of another similar one in Space SE's What cosmic ray sensor is attached to this Balloon?

From the video:

NASA’s Wallops Flight Facility in Virginia manages the agency’s Scientific Balloon Program with 10 to 15 flights each year from launch sites worldwide. Northrop Grumman, which operates NASA’s Columbia Scientific Balloon Facility (CSBF) in Texas, provides mission planning, engineering services and field operations for the program. The CSBF team has launched more than 1,700 scientific balloons in the over 35 years of operation.