Because Vanilla+ is a sort of modpack, each part of the mod has its own license:

Parts : Mk2 Battery, Mk2 Decoupler & Mk2 Separator (by JoePatrick1) are under the following license: All rights reserved

Parts : Mk3 Airline Cockpit & Mk3 Space Shuttle Nose Cone (by K.Yeon) are under the following license : Creative Commons

The rest of the mod is under Creative Commons license.