I don't know if there is another level of appeal available but NTSB says FAA has the right to regulate drone flights. NTSB: Drone Flights Are Subject to FAA Regulations - NBC News (http://www.nbcnews.com/tech/tech-news/ntsb-drone-flights-are-subject-faa-regulations-n250876)

In a different article, it stated simply that the FAA can regulate their flight, so stay below 400 feet, and don't endanger people or property.

Pirker's attorney(s) are quoted as saying, "The more significant question of whether the safe operation of drones for business purposes is prohibited by any law was not addressed in the decision, and is currently pending before the D.C. Circuit in other cases being handled by Kramer Levin (law firm).”

So we are still in no-man's land...