Based on the provided results from Brave Search, it appears that the US government has approved funds for geoengineering research, including assessments of "solar climate interventions" including "proposals to inject material [into the stratosphere] to affect climate."

1

The $1.4 trillion spending bills that Congress passed included a little-noticed provision setting aside at least $4 million for the National Oceanic and Atmospheric Administration (NOAA) to conduct stratospheric monitoring and research efforts.

2

The National Oceanic and Atmospheric Administration's (NOAA) Earth System Research Laboratory is authorized to conduct geoengineering research in the US airspace, with a $4 million funding from Congress.

3

However, it's worth noting that the US has opposed a UN plan to study geoengineering to combat climate change, and instead, the US government has authorized funding for geoengineering research through the NOAA.

4

Additionally, the Federal Aviation Administration (FAA) is responsible for regulating all aspects of civil aviation and providing air traffic control, including the regulation of geoengineering operations in US airspace.

5

It's also worth noting that Florida has banned weather modification and geoengineering in state airspace, but the federal government has not implemented a similar ban.

6

References:

1 Zero Geoengineering - The US government has approved funds for geoengineering research

2 Zero Geoengineering - The $1.4 trillion spending bills that Congress passed

3 Quarterly Review III (part 1) - Geoengineering Monitor - The National Oceanic and Atmospheric Administration's (NOAA) Earth System Research Laboratory

4 The US Opposed a UN Plan to Study Geoengineering to Combat Climate Change

5 U.S. National Airspace Modernization - Skymantics - The Federal Aviation Administration (FAA)

6 Some climate change solution research at risk as Florida senate moves to ban geoengineering testing