Carriers travel at 3 times normal speed between two stars with warp gates.
A gate can be destroyed at any time, and any carriers that were using the gate for accelerated movement will slow to normal speed.
Normal hyperspace range restrictions apply when traveling between warp gates.
The price to construct a warp gate is determined using the natural resource of a star in the same way price is determined for Economy, Industry and Science.
Read more about building at Stars