I have recently released a sprite kit that allows you to create futuristic planes or ship, similar to the ones you see in my game DefOp. The kit contains multiple small parts, allowing you to mix and match to create awesome looking crafts. Suitable for top-down view games.
The Futuristic 2D Sprite Kit costs $5 and you can get them at the following sites:
If you have used these sprites in your games or projects, feel free to drop me an email over at developer [at] livingtheindie.com. Would love to see what you have done. Cheers!