[Darksheare]

A Spherical airship requires four motors at 'opposite' corners, or at least two on opposite sides.
By their shape and such, they can move in random directions fairly abruptly.
Some engineer type built one that's painted to look like a huge globe of teh Earth, and he was doing fairly odd maneuvers with it, like random bumble-bee like turns and spins.
(Made it 'dance' and spin in place too..)

Still, it's only conjecture on my part as to what it might be.

[lodwick]

Bingo!

[grannie9]

But this thing didn't fly per se.. it just floated lazily around. Drifted...up and down and around and then it would follow the earth for short distances.. and then go back on itself and circle up and around and down.. Light as air.

If I didn't see the stabilizer type things..flat straight lines, it would look like a perfectly round white baloon. I think the things that went thru it were metal, and would catch the sun every once in a while when it turned a little.. If it wasn't for the cloud I could have watched it for an hour as it drifted past.

The size to my naked eye was about the size of 'o' on my test here.. Only and Eagle Eye like me would have ever noticed it.. :)