Here is this morning's flight, looks like they launched the Pegasus rocket while at FL390 going eastbound.
https://www.flightradar24.com/data/a...140sc/#be5deb5
https://flightaware.com/live/flight/...225Z/KXMR/KXMR
The L1011 is owned and operated by Orbital ATK under NASA contracts:
https://spaceflightnow.com/2015/04/1...s-carrier-jet/