What are these circles? (pic)

[agkm800]

Every time I fly (US domestic) I see these circles and still have no idea what they are.

 

[wordoflife]

Cool. Never seen those before.

Approximate location of pic? (I'm guessing you were either landing or taking off, since you were close enough to see the ground)

 

[joec1101]

Alien crop circles

 

[mobilehaathi]

center pivot irrigation

 

[justperry]

You might find the answer here, an old thread on another site.

http://www.gearthhacks.com/forums/showthread.php?10744-Strange-black-circles

^^Yup, same.