To Attack
To Assault
する verb
Remember how 襲撃 is an assault or attack? This is the verb form, so it's to attack or to assault.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
飛行機で巨人を襲撃することができるようになるとは、知る由もなかった。
Little did they know they would be able to attack titans by air.