The future of military tech is supposedly hypersonic missiles, stealth drones and suicide drones. I'm going with large-scale air force experiments with a new line of drones, possibly with a 'psy-op' angle. While the Democrats sabotage everything possible for the upcoming Orange-Man-Bad presidency (such as selling off portions of the border wall), they want to distract people with 'mysterious' unidentified aerial phenomena.
There be aliens/Iranian motherships launching drone squadrons/Chinese stealth balloons afoot.
(I haven't really spent much thought on this. In case you haven't noticed. ;) )
Partly mass hysteria. Once people start to look up into the sky, they see lights they haven't paid attention to before.
Those lights now become drones, every single one.