LiPos can burn when abused, but there are also reports where a fire
(sometimes more like an explosion) started while the batteries were not in
use. A friend of mine who is working in R&D of LiPo batteries confirmed that
this may happen in some rare cases, so I definitely would not use them in my
glider. I do use A123 LiFe cells (different chemistry than LiPo!) in my self
launcher and I am very happy with the power and capacity they offer.

Michael