Modern hirotwo teo headcanon: Hiro owns a motercycle and it’s name is strelitzia. He takes zero two on it before and after school, and zero two will put cute stickers on it once in a while and Hiro doesn’t mind

I love this, especially the bit about Zero Two putting stickers on it, but consider this as well:

They buy a run down motorcycle together and spend the next couple years repairing it before going on a summer road trip together.