Lighted object brighter than surrounding stars started darting erratically and fast in a zig-zag pattern across the sky,stopping occasionally before darting again much faster than any plane or helicopter we've ever observed.The object was too high to distinguish its shape, it appeared as a point of light. when a commercial airliner started approaching the general area, the object moved far away from it, like it was trying to avoid detection. when the plane left the area the object moved back to its original position and then started darting around again. hard to determine how high it was, but it didn't seem to change elevation. this occurred for over an hour before the object disappeared.