Most people even do not understand what they’re looking at. I’m not sure of what race of aliens are we witnessing here, but it could be the Greys from Zeta star systems.
This is the antigravity force field in action, we can hear well the electromagnetic field drive starts spinning.
And when it achieved enough rpm of this field, the Grey add voltage DC charge to tubular capacitors that are positioned above the spinning thorus field.
Higher the voltage, faster take off! Charger plasma can be seen during the takeoff, that little flash. Charged plasma ionized air suspended in an antigravity force field.
These amazing ships can travel up to 30,000 miles/hour in our atmosphere.
The greys probably realized that they were spotted and was not sure how us, primitive beings to them, might react.
We are arrogant if we assume that planet Earth is the only planet with life in the Universe. Not only that we are not alone, but different races of aliens are living among us today. Some of them want to take our place while others are helping us to stage 2 civilization.