The Feliner was the first inter-stellar vehicle developed by the ThunderCats. As the ThunderCats continued to form alliances and friendship with beings from other planets, as well as the introduction of alien enemies, they needed a spacecraft that was capable of deep space travel. Thus Panthro began work on the Feliner. He managed to complete the entire craft but was missing only one component to make it work, the Hyper-Space Mega-Condenser. Fortunately, the ThunderCats were able to obtain this part from the wreck of the RatStar after it was destroyed in a battle with them.

The Feliner was the biggest vehicle owned by the ThunderCats. It had enough space to fit almost all of them comfortably. It had a cat-shaped cockpit, giant wings and legs which changed positions depending on whether the Feliner was landing or flying. The Feliner was also capable of traveling at light speed, enabling it to reach very far planets and constellations.

It was armed with laser whiskers, which could extend out of the sides of the front. The ship would then spin very fast turning itself into a weapon which could cut through most objects.