No value whatsoever in any of them except possibly the .NET. The .COM is marred by the hyphen.
Why the word "American"? Maybe some company in the USA would brand itself like that. But how often are new companies formed in the flight industry? Not often at all.
Maybe overseas people look for specifically American planes. But I'm not sure they'd need to pay extra to build a website on AmericanPlanes.com -- let alone the .NET.
Maybe a hobbyist who likes aviation and militaria will want to create a fan page for American planes. But hobbyists pay $10 to register new domains or at most low $xxx. The .NET won't be that guy's first choice.
So unless you're going to develop it because you yourself are than fan ... or unless you know of specific businesses to sell to, just get rid of the .NET as well.
For the price of those 5 domains, you could get something better.