According to defense experts, these are advanced designs but there is still not enough information to make specific comments.
Reuters reported that both fighter jets do not have a vertical take-off, a feature that helps the aircraft maintain stability with a computer system rather than a mechanical structure. The larger aircraft has a diamond-shaped design with three air intakes - both sides of the body and one on the roof - a rare configuration. The smaller design has a more traditional layout but also lacks a vertical tail.
A common feature of both models is the design that does not use square angles, a typical factor in reducing the possibility of radar detection.
Euan Graham, senior analyst at the Australian Strategic Policy Institute, commented that these designs demonstrate the creative and experimental spirit of the Chinese aviation industry. "While there is much debate about its effectiveness, it is still a unique design," he said.
China's Ministry of National Defense has not commented, while the US Department of Defense said it had received the information but did not add anything beyond the content of its annual report on the Chinese military.
Currently, the US is implementing the "Next Generation Air dominance" (NGAD) program to develop a sixth-generation fighter, while Europe and Asia are collaborating in the Global Combat Air Programme program, with a recently announced British-Japan joint venture.
Images of China's larger aircraft have been confirmed through video recording the flight over Chengdu, comparing with terrain features and satellite images. However, the specific date of the video has not been verified.
China's testing of these new designs during the day, right on large, easily-aperceived cities, is considered by experts to be "remarkable".
