Ah,the myth persists. I wonder if the guys in a field with a tractor and a plank creating patterns ever thought people would be still thinking it was aliens all these years later. Why would ET come here to create patterns in fields? Surely by now they'd have moved on to farming humans for milk and honey..
Our civilization will develop interstellar travel technologies (starships carrying robots and human embryos) in a couple of hundred years. There's a high probability that on stars (billions of years older than our Sun), this technology developed billions of years ago.
I'm not 100% sure who makes crop circles. Probably both. Or maybe just people with sticks, because we're the smartest people in this part of the galaxy :)