SPOILER WARNING: Second Formic War plot details follow.
A High-Velocity Interplanetary Craft (HVIC), more commonly known as a Zipship was an incredibly fast transportation vessel used by the International Fleet.
Design and Function
Zipships were essentially an upgraded version of a Quickship. They were faster and safer.
Zipships were created in the three years after the end of the First Formic War. After the invention of the Ansible, they were used to send the new device to the various Fleet outposts and ships throughout the solar system.