This category can consist of ordinary debris (plastic bags, litter etc.) or various forms of kite.  Undeniably some UFO sightings have been generated by such objects, as some kites are capable of manoeuvres seemingly impossible by any man-made craft, and that in some cases their holographic foils can reflect the sunlight in a kaleidoscope of colour.

Telltale signs: Motion with the wind (if debris), buffeting or rocking (if stabilized as a kite), relatively low height (only small debris will be taken quite high and will
therefore be too small to be seen), relatively small size.