Since 20 km flight ceiling is around 65600 feet, I am fairly sure that this is the Two-Stage-to-Low-Orbit (aka SR-75 + Dart) spacecraft which is either an NRO (National Reconnaissance Office) asset for General White House directed Observational Satellite imagery OR its a CIA (Central Intelligence Agency) asset used for tactical operations imaging for special forces (JSOC or SOCOM).
Since it's been detected over the New York area as the seeming final destination, I'm fairly sure the main operating base is probably near Westchester County or the Near Lake Champlain, NY in one of the smaller operating bases. If this is an NRO operation, it will be a North Korea observation and/or Iran Missile Base Observation run starting at around 135000 feet to as high as 300000+ feet. There is also the possibility of a Cuba and Venezuela run for looking at recent weather damage, economic and general political observations.
If this is a CIA run, it will over North Eastern China, Eastern Russia and possibly Afghanistan, Pakistan and/or Kashmir (India) for a logistics scouting run used to direct small special operations forces on tactical missions such as hunting for stray nukes, killing bad-dude warlords and/or sabotaging 3rd party or proxy forces/insurgents and their assets in those regions.
They may have also sent it over the East Coast for an eventual wide arc around or Over Florida to a New Mexico or Arizona landing which usually done when maintenance or upgrades on the smaller parasitic Dart spaceplane needs to be completed since Arizona/New Mexico contains TEST and MAINTENANCE facilities!