I saw a book titled
"How Aircraft Move Through the Air".
But is that correct? I think aircraft is the singular. So Would it be "moves" or "moved"(in case of past sentence)?
Am I wrong? Please let me know. Thanks.
Aircraft is both singular and plural. Like sheep.
If it is used in a way that could be singular or plural, the singular is denoted by use of an article.
"How aircraft move through the air"
"How an aircraft moves through the air"
A definite article can be applied to the singular or plural (the plural potentially acting more like a mass noun).
"How the aircraft moves through the air"
"How the aircraft move through the air"
Both are valid, but with different meaning.