That is all they have ever been, just balloons filled with Helium. They even have a top secret aircraft carrier size floating platform, via the Helium or both that and Hydrogen lift bags. Hardened super structure held up by helium... Just like described in the book of Obadiah. ITS A ONE PAGE BOOK IN YOUR BIBLE. LOOK INTO IT.. God will bring them all down, on the last day or sooner. Read Obadiah