That'll be one of those Chinese lanterns
First one I saw, thought it was a UFO!
(Juan Quar is clinging to her front teeth on, Sun 8 Aug 2010, 18:05, 1 reply)

Yup
I'll agree they look amazing, individually or en masse.

Only snag is, it's essentially littering in an aesthetic manner.

The typical mass-produced, low-cost, UK sold chinese lantern is paper and metal wire. The paper isn't that big a deal on it's own, but the metal wire lasts and lasts; potentially harming wildlife at land or sea depending on where it lands.

Then there's the other complications: The fire risk (modest but real), and the hazard to aerial navigation.
(The Incredible Sulk Finally remembered his password on, Sun 8 Aug 2010, 18:40, closed)

I think you can get
less awfully dangerous ones. But I suspect they still have issues
( Citizen Cavy Admires your passion for conformity, Mon 9 Aug 2010, 19:42, closed)

absolutely correct
I should have explained more clearly.

Yes, you can get ones which are meant to be 'better', in that they theoretically avoid *some* of the problems; but even if you choose a metal-free construction (and I think most people, if given the choice, won't select a more expensive option for something 'disposable'); all designs still suffer inherent problems.

Additionally; something I missed last time: Near open water, any type can also cause false alarms for Search & Rescue, due to their (perceived) resemblance to distress flares. Not directly lethal; but sooner or later one of finite crews could be out chasing false alarms with good intent, and won't be able to respond in time to a real emergency happening elsewhere.

This BBC report elaborates on the general topic: news.bbc.co.uk/1/hi/uk/8490524.stm

As an aside; I wonder if they'd still look allright if somehow tethered? Sort of a "night kite". That way, when they burn out they'd sink back down for easy cleanup. Snag is, you'd need a seriously huge garden, NO overhead lines or trees nearby, dedicated 'fire watch', and a lightning risk of 0% for starters.
(The Incredible Sulk Finally remembered his password on, Tue 10 Aug 2010, 8:23, closed)