This whole airship bit is great. In the previous chapter we got a bit of information on Killua, and now we really see the differences between Gon and Killua. Gon doesn't give up even when things seem hopeless, while Killua analyses the situation and gives up as soon as he realises he can't win. I like how pretty much all of the groundwork of the characters is set up already in the first arc.
We also get to see that Killua is very much a killer, even if he left his family. The morality of our main characters is definitely not black and white.
