Balloon Dragons are so named because they are filled with a gas that makes them almost lighter than air, similar to balloons. However, they are not prone to bursting, as they are covered in tough skin and can deflate themselves if necessary. In addition, they generally are slow moving. They use their gas bladders to float to the tops of trees, where food is more abundant. They can shift their weight from their backs to their fronts, allowing them to reach leaves and fruit.
Lightfloat's grouchiness led to him ducking for cover during the Great War; yes, he was crotchety, but that didn't mean he wanted to see any of his Weyr hurt! Even the hatchlings who used to pester him so, making him growl and snap with anger. To see even the hatchlings caught up in Flameflow's razing wrath... It was horrifying. In the aftermath of the War, Lightfloat found himself a kinder, gentler dragon, trying to avoid all sources of conflict. Sometimes even the echo of a roar from outside the weyrlands will send him reeling into his mind with memories of the tiny bodies of hatchlings who couldn't get away in time, hatchlings out of their parents' protection... He has taken a mate since the end of the War, and they've adopted hatchlings together, as if to make up for his grouchy treatment of the hatchlings who have died.
These days, Lightfloat does his best to be kind to all around him; even if the same things annoy him, no longer does he snap impatiently. Life is too short.