In the above picture, a US-2 amphibious aircraft is taxiing on the runway, with a blue and white painted body that looks particularly tall. The lower half of the aircraft adopts a hull design, while the upper half features wing propellers, forming a unique shape of "half airplane, half ship". The design core of amphibious aircraft lies in balancing aerial flight and water navigation. The bottom of the hull structure is equipped with a V-shaped or U-shaped sliding hull, which can reduce water resistance and resist surges; There are usually floats below the wings on both sides to maintain lateral stability during water sliding. This design allows it to take off and land normally at land airports, as well as complete taxiing, takeoff, and landing in open waters, achieving free shuttle between water and air. As a multifunctional aircraft, amphibious aircraft are widely used in military and civilian fields. Taking US-2 as an example, the aircraft can take off and land in harsh sea conditions with a wave height of 3 meters, carry search and rescue and medical equipment, and perform tasks such as maritime patrols, casualty transportation, and anti submarine reconnaissance; When extinguishing fires in forests, it can quickly fetch dozens of tons of water and accurately inject water into the fire scene, with efficiency far exceeding that of helicopters; In islands and remote lake areas with inconvenient transportation, passenger and freight transportation can be undertaken without the need to build dedicated airports, as long as there is a sufficiently open water area, which greatly reduces the cost of infrastructure construction. Each country's amphibious aircraft has its own characteristics due to different mission requirements. The Russia-200 is mainly focused on firefighting and uses jet power, ranking among the world's top in terms of water pumping efficiency and flight speed; The Chinese AG600 "Kunlong" is currently the world's largest amphibious aircraft under development, capable of carrying out forest firefighting, maritime search and rescue, and transportation of materials to offshore islands and reefs; The Japanese US-2 emphasizes adaptability in maritime search and rescue, significantly reducing takeoff and landing distances, and can be used in narrow waters; The Canadian CL-415 has become one of the most popular firefighting amphibious aircraft in the international market due to its excellent low altitude and low-speed performance. The development of amphibious aircraft reflects humanity's unremitting exploration of cross-border applications of aircraft. From early wooden floating seaplanes to modern aircraft models using composite materials and electric control systems, although the technological forms have continuously evolved, the core concept of water air integration has remained unchanged. This type of aircraft fills the functional gap between aircraft and ships, playing an irreplaceable role in fields such as ocean development, emergency rescue, and national defense security. It is known as the "floating boat" that connects the ocean and the sky.