Donut shaped craft or large balloon

Is someone releasing very large donut shaped balloons that fly very high?  The whole family was just outside playing ball and riding bikes on street out in front of our house and we saw this thing floating through the sky very high up.  It looked just like the one in the article I linked below.  It was very high and very large as several commercial jets flew by as well and it ended up going into the same clouds so we could make a decent comparison.  It didn't make any abrupt moves other than to come to a dead stop and then proceed a couple times.  We watched it for about 5 minutes before I lost it in the clouds.  My guess is someone released a very big circular donut shaped balloon... but if so I'd think that could be dangerous to air traffic flying so high up.
http://www.ufosightingsdaily.com/2012/03/donut-shaped-ufo-seen-over-new-york.html