It was 2016 when China started building its 2nd aircraft carrier, but are they already getting ready for a third one? Apparently yes.

New satellite images suggest that China’s building up its naval airbase and is getting ready for their fourth aircraft carrier. A video has been circulating online showing China’s KJ-600 on a test flight over the northwestern city of Xian, the headquarters of Xian Aircraft Industrial Corporation.

According to defense experts, this is a clear sign China’s getting ready for expansion. The satellites in March also spotted two FC-31 Gyrfalcon stealth fighters together with a couple of J-15 carrier-based fighter jets at the People’s Liberation Army (PLA) facility in Liaoning province. Experts assume these are intended for the new aircraft carrier as well.

There is ongoing speculations, too, that the FC-31s will be the main carrier-based fighter jets assigned to the new aircraft carrier. However, a source close to the Navy said the J-15s are more likely to be the only ship-borne carrier for future assignments.