Umika is excited to start building a rocket with Yu. However, she is then confronted by her classmate, Haruno, who just happened to spot Umika and Yu sneaking into a lighthouse after school...
It flies thanks to the air 
pressure inside the bottle.
.إنّه يطير بسبب ضغط الهواء في القنّينة
Vola grazie alla pressione dell'aria
 all'interno della bottiglia.
Ele voa graças à pressão
de ar dentro da garrafa.
Она поднимается за счёт
давления воздуха в бутылке.