Even the successful flying boats proved, in the end, uneconomical.即使是成功的水上飞机最终也未能盈利。He watched the seaplane landing on water.他看著水上飞机在海面上降落。The engine of the seaplane started up.水上飞机的发动机启动了。We watched the seaplanes landing on the water.我们看着水上飞机降落在水面上。The engine of the seaplane started up.水上飞机的引擎启动了。