飞行艇（Flying boat）是一种有着船体的定翼水上飞机，可以降落在水面上。跟浮筒飞机不同，主要是使用机身来产生浮力。飞艇或许会以下翼或突出像翼的副翼产生的浮力来达成稳定，不过现行的设计多仍与浮筒飞机一样在两侧机翼加装浮筒保持水面平衡。飞艇或许是二十世纪前半最大型的大气载具，这个地位直到二战时才被轰炸机所取代。它们的好处是可以用水体代替昂贵的路上跑道，使它们在战间期担任国际航空线的基础。也常被用于海上巡逻与空海救援，但也有飞行艇加上起落架故也可在陆上机场升降。

在二战后使用率逐渐缩小，部分原因是战争期间对于机场的投资。在二十一世纪，飞艇使用在几项合适的用途，如对森林大火投水，造访未开发或无道路的地区。

A flying boat is a fixed-winged seaplane with a hull, allowing it to land on water, that usually has no type of landing gear to allow operation on land. It differs from a floatplane as it uses a purpose-designed fuselage which can float, granting the aircraft buoyancy. Flying boats may be stabilized by under-wing floats or by wing-like projections (called sponsons) from the fuselage. Flying boats were some of the largest aircraft of the first half of the 20th century, exceeded in size only by bombers developed during World War II. Their advantage lay in using water instead of expensive land-based runways, making them the basis for international airlines in the interwar period. They were also commonly used for maritime patrol and air-sea rescue.