If Virgin Orbit build LauncherOne in KSP
LauncherOne is an Air-Launched Rocket, that is similar to Virgin Galactics SpaceShipTwo. However instead of launching people, it launches satellites into Orbit. For now, it is a two Stage design, but there might be third Stage added later, as some renderings suggest. This Stage design is already special, because it is the first fully liquid fueled Air-launcher, that brought payloads into Orbit.
Today's guessing Question:
Which type of Airplane is used to bring LauncherOne to it's launch altitude?
Hint: Manufacturer Boeing.
Answer in the comment section!
The Rocket was replicated in Kerbal Space Program.
No mods were used, but DLC's might be required.