Okay, so what do you think the actual culprit is for these sightings?
http://www.cufon.org/cufon/ifo_list.htm
Here's a fairly comprehensive list of plausible explanation for UFOs in general complied by Donald Menzel, a noted debunker of the 50s and 60s. What on this list would be most likely for the China ones, I'll leave that to the guys with the non-plausible answers. But below are my personal picks that I dedicate to them for sarcastically skirting the issue.
Matches (while sometimes being mistaken for UFOs, they are most commonly mistaken for Will‘o the Wisp due to the abrupt way in which they are extinguished by the smoker)
smoker lighting pipe – usually reported as a UFO igniting booster rockets while achieving escape velocity
flicked cigarettes (very common when drunk guys are pissing outdoors)
reflection from glasses – I wear glasses and have been on the cover of the National Enquirer several times and once made a guest appearance on the UFO Hunters.
The falling leaf effect – mostly reported by people under the influence of LSD or other hallucinogens
Ghost of the Brocken – this one speaks for itself
insect swarms - particularily in tropical climates
tumbleweeds – mainly reported by lonely cowboys
icebergs
[*
the updated and revised list also includes two new entries - the iceberg tumbleweeds (related to iceberg lettuce) and the tumbling icebergs (not to be confused with Bjork's new band)]
domed roofs – this originated from explorers to the Arctic seeing Superman flying out of his dome-roofed Fortress of Solitude and then mistaking it for the Mother of all Mother Ships
milkweed seeds – frequently mistaken for armadas of invading fleets releasing their Death Gliders.
feathers – especially when seen on flying birds at dusk and dawn
paper and other debris – The possibilities are endless considering their versatile and varied nature
kites – particularily deceptive because of their tendency to chaotically jerk hither and yon while hovering over the same general area and its erratic movements are mistaken for right-angle turns and other laws-of-physics defying acts
leaves – Autum in New England in particular
spider webs – will the wonders of nature never cease?
Moths – mainly when they fly into a bug zapper and they are mistaken for UFOs that crash and burn
advertising – ‘nuff said
illuminated bubbles – WTF?
sewage disposal – WTF?
soap bubbles - Lately, there's been a rash of sightings in Pocetello, Idaho that were later discovered to be soap bubbles. It turns out it was a publicity stunt by Dove Bar Soap. The company was charged by the local authorities for being in violation of the Orson Welles alert and were required to supply the whole town with free soap for a year.