Artist's commentary
Burn... Hoppo's Cosmo...!
"Now... to the ultimate level...!"
Akutan's Reppu Punch! Hard to translate this, Akutan Reppu-Ken is a parody of Pegasus Ryuusei-Ken/Pegasus Shooting star Punch, Akutan being the Akutan Zero plane, and Reppu is well, the Reppu plane. Basically, it's a mix between Akutan Zero and Reppuu's names, and adding -ken/punch at the end. And "Zero's Strong gale Punch" might be a tad too much, while losing the Reppu reference)