The fly over is a fact gathering terrain mapping to aid the CCP in their initial land invasion from Canada into the most unpopulated northern states.
The initial attack will include a power grid failure to large swaths of the US, which will cause chaos and divided resources while Chinese infantry take their first territories.
Securing the U.S. Power Grid: President and Commerce Department Sound the Alarm
https://www.hklaw.com/en/insights/publications/2020/05/securing-the-us-power-grid-president-and-commerce-department
Stopping Chinese Communist Involvement in the Power Grid Act would continue Trump’s ban on equipment purchase or use from six adversaries, including China
https://govtrackinsider.com/stopping-chinese-communist-involvement-in-the-power-grid-act-would-continue-trumps-ban-on-7c0372efb2f