The aerogels would be thermal insulators under an opaque coating. My Children of a Dead Earth favorite is a thin layer of something reflective for short-burst

The aerogels would be thermal insulators under an opaque coating. My Children of a Dead Earth favorite is a thin layer of something reflective for short-burst thermal reflection, under that something that can take high temperatures like carbon-carbon for sustained lasers, and then a big slab of aerogel to keep that heat off of the more delicate bits.