Interesting - was looking into how the heck they pulled off the permit.. still not clear but found a little more info here

https://gizmodo.com/candy-crush-drones-nyc-bird-migration-1849740195

"In an email to Gizmodo, an FAA spokesperson said “Pixis Drones is responsible for coordinating with local law enforcement, park police, city officials and others as appropriate.” These shows require waivers that normally restrict users from operating more than one drone at a time. The agency spokesperson further said it reviews drone shows to maintain safety, including procedures in case drones fail or if an aircraft gets too close. Drone operators are meant to restrict where they fly to a select area using GeoFencing technology.

It’s migratory season for many bird populations moving from Canada down to Central and South America, and bird advocates said this drone show could not be happening at a worse time. "

https://www.engadget.com/drone-swarm-ads-over-new-york-city-195042672.html

"Pixis is jumping over multiple legal hurdles to make the campaign happen. New York City's Avigation Law bans drone flights altogether, so any aerial sales pitches have to remain within New Jersey's borders. The company also had to obtain both a Federal Aviation Administration waiver (to fly in federal airspace) and a special permit from New Jersey (to operate from Liberty State Park)."