Jefferson says, "An explosion, by definition, is matter turning to energy, right?" The only type of explosion that converts matter to energy is nuclear fusion (H-bombs). Atomic bombs release the binding energy that holds atomic nuclei together (the strong nuclear force). Chemical explosions release energy that holds atoms together in molecules (electromagnetic force). There are also mechanical explosions (like a bursting high-pressure air tank) and pure kinetic energy (like meteorites hitting the ground).
Jennifer ("Lightning") and Jefferson ("Black Lightning") both fly up to "the ionosphere", which begins at a height of about 30 miles. At that altitude, there would be far too little air to breathe, talk, or stay alive. For comparison, the summit of Mount Everest is about 5-1/2 miles above sea level, and passenger aircraft rarely get as high as 8 miles.