It’s true many people are confused between seaplanes and helicopters. I think there are two aspects related to that situation:
Firstly, it’s about professional aviation knowledge. In Vietnam, helicopters and seaplanes are not so familiar to everyone, resulting in the above confusion.
Secondly, it is related to the language issue. In Vietnamese, the words ‘helicopter’ and especially ‘seaplane’ are not popular with everyone because we often just say ‘plane.’ Especially, ‘seaplane’ in Vietnamese is translated into a long and unfamiliar term with five words: ‘máy bay thuỷ phi cơ.’
Improving professional aviation knowledge might be challenging for better understanding and confusion avoidance. So I suggest we can resolve the language issue instead. We can avoid confusion by using the terms ‘floatplane/flying boat’ for seaplane, which is ‘máy bay đáp nước’ in Vietnamese. As for ‘helicopter,’ we call it ‘máy bay lên thẳng,’ an aircraft taking off and landing vertically.