A full-scale model of China’s J-31 stealth fighter prototype has appeared on the flight deck of the Chinese navy’s aircraft carrier mock-up, fueling speculation that the radar-evading jet could become part of China’s carrier air wing.

If so, China would enter the race alongside the United States to be the first to deploy a stealth jet on a flattop. The U.S. Navy is struggling to develop the F-35C stealth fighter to fly from the American fleet’s 10 large carriers starting no earlier than late 2018.

China often builds mock-ups of its new warships on land before constructing prototype vessels. In the spring of 2014, Chinese naval architects began assembling a model of a huge new missile cruiser on the campus of a technical institute in Wuhan.

The cruiser model joined an older mock-up of China’s first aircraft carrier Liaoning—actually a refurbished Soviet flattop. Before placing Liaoning into limited service in 2012, the Chinese navy tested the rebuilt carrier’s systems on the model at Wuhan.

And now a photographer has spotted a model of the J-31 fighter on the mock-up carrier’s deck. Chinese engineers could be testing the plane to see whether it can safely maneuver on Liaoning’s 1,000-foot-long flight deck. Liaoning lacks catapults and instead launches planes by way of a bow ramp.

The Chinese carrier is considerably smaller than American flattops.