A grey-hulled aircraft, roughly the length of a regional jet, was recently spotted hovering just above the surface of the Bohai Sea. Unlike a traditional seaplane, this aircraft uses a compressed air cushion created by its own wings to stay afloat, allowing it to glide just a few meters above the water. Known informally as the "Bohai Sea Monster" by Chinese internet users, the aircraft first appeared in grainy photos in July 2025 near a port in northeastern China. More detailed images surfaced in May 2026, revealing more about the aircraft's design and capabilities. These images confirmed that China is not simply building a seaplane, but something more advanced and specialized. The initial images of the aircraft, captured in July 2025, showed a four-engine aircraft near the Bohai Sea, a body of water between China and the Korean Peninsula. The photos were blurry at first, obscuring parts of the aircraft's nose. However, clearer images circulated a few days later, giving a better view of the aircraft's silhouette. In May 2026, even more detailed photos appeared online, shared by military analyst Andreas Rupprecht. These images showed the aircraft being lifted by a crane, revealing features like its landing gear, suggesting it could operate from both land and water. The images also indicated the aircraft was smaller than previously thought. The principle behind the aircraft’s flight is based on ground effect, a phenomenon where a wing flying close to the surface compresses the air beneath it. This creates a cushion of air that reduces drag and allows the aircraft to stay aloft with less energy than a traditional plane. This makes the aircraft heavier than a typical seaplane, faster than a ship, and nearly invisible to radar systems that scan higher altitudes. The aircraft glides just a few meters above the waves, making it difficult to detect by conventional radar. Unlike traditional seaplanes, it doesn’t rely on floats or a hull; instead, it uses pure aerodynamics, operating just above the water’s surface. The concept of such aircraft is not new. The Soviet Union pioneered the development of ekranoplanes, with the Lun-class being the most famous. These vehicles were classified as maritime vessels due to their ability to travel just above the water’s surface. The Soviet KM, or "Caspian Sea Monster," was an experimental prototype that first flew in 1966. However, the project was abandoned due to high costs and unclear military use. Today, China is advancing this concept with modern materials and design, recruiting Russian engineers and using advanced composites to build a lighter and more efficient aircraft. The Chinese version, while inspired by Soviet designs, has a different structure, featuring four engines on short wings and a wide tail, suggesting a focus on both speed and versatility. While China has been quietly developing this technology, the United States has seen setbacks. In 2022, the U.S. Defense Advanced Research Projects Agency (DARPA) launched the Liberty Lifter program to build a ground effect seaplane capable of transporting cargo across the Pacific without a runway. However, the program was canceled in 2025 after spending nearly $98 million without producing a working prototype. In contrast, China’s "Bohai Sea Monster" appeared in clear images in May 2026, showing potential weapon carriage points under its wings. Analysts believe the aircraft could serve a dual purpose, combining rapid troop transport with coastal strikes. While some question whether it is yet operational, the aircraft’s stealth capabilities and advanced design mark it as a significant development in modern military aviation.