14 C.F.R. § 103.20
Flight restrictions in the proximity of certain areas designated by notice to airmen
No person may operate an ultralight vehicle in areas designated in a Notice to Airmen under § 91.137, § 91.138, § 91.141, § 91.143 or § 91.145 of this chapter, unless authorized by:
(a) Air Traffic Control (ATC); or
(b) A Flight Standards Certificate of Waiver or Authorization issued for the demonstration or event.