My guess is that was a VTOL with efficient aerodynamics or jet drone to loiter and power for racing-class activities. If it flies, something like https://fusionflight.com/jetquad/ could pull it off.
Possibilities:
0. Rich, drone expert prankster, or startup showing-off to their buddies/customers "getting away with something" highly-illegal.
1. State actor demonstrating strength, vulnerabilities, and/or doing low-level recon.
I think 2. can be ruled out. It’s hard to imagine a terrorist group doing this considering the risk of getting caught. Much easier just to drive a truck into a crowd or something.
I disagree. The truck going through the crowd model requires a sacrificial group member. In our country, the lack of terrorist group members makes their individual value higher. that makes an attack that has a higher capex cost more appealing, such as sacrificial drones.
A swarm of two dozen drones costing less than $50k could foul all of a passenger airplane's engines within a few thousand feet of takeoff. The evidence would be pretty junked up and there is no easy way to trace it back to the controller while it's happening. No sacrificial terrorist cell member needed.
Possibilities:
0. Rich, drone expert prankster, or startup showing-off to their buddies/customers "getting away with something" highly-illegal.
1. State actor demonstrating strength, vulnerabilities, and/or doing low-level recon.
2. Terrorists scouting targets and/or probing vulnerabilities.
3. Military demonstrating vulnerabilities for civilian awareness and corrective purposes.*
4. Military seeking budget for anti-drone.*
5. Military-Industrial Complex drumming-up business for anti-drone.*
* Conspiracy theory-ish