I am not a mystical sort of person so my theories on crop circles are more nuts and bolts than most, because I think that some one is landing on our planet whilst still in the 4th dimension that is the short cut which must exist for them to get here, think about that, nearest place 26 light years away, nearest life we estimate at 30 years away, so there and back 60 years plus 30 years old before you start learning about space etc. .So no experienced pilots even with a life span of 200 years you only have time for one flight .
So there must be a short cut, So if you were going to invade you would need to conceal your landings to be safe from attack and if you wanted to invade you would need troop carriers supply ships, gun ships, communication ships, they would all need to be tested. Hence you land them in a crop field on their maiden voyage to try out their landing systems there must be a different set of controls in that short cut you must be able to just twitch a control and be miles out into space in no time they video the landing in the crop field and the pattern shows a good landing or adjustment is required .MAYBE THEY DONT WANT TO MAKE THE SAME MISTAKE AS THEY DID AT ROSWELL.