The impact depends on your license type:
Floating licenses: Will continue to work in air-gapped environments. Unity provides a floating license server archive and step-by-step instructions for creating client configuration files.
Nodelocked to Named User License (NUL) migration: Named User Licenses are not compatible with air-gapped environments. If you're currently using Asset Transformer Studio Nodelocked licenses in an air-gapped environment, we recommend upgrading to Asset Transformer Studio Floating licenses instead. If you're using an air-gapped environment and are unsure about the migration path, please reach out to your Client Partner to discuss the best licensing option for your setup.