In my Fantasy/sci-fi universe there exists a lighter than air gas, that is non-flammable, while having density similar or even smaller than hydrogen (I will post some questions related to this gas in the future). This gas, combined with light and strong materials used in universe, permits making big airships that can lift big weight, but not making steampunk-looking flying battleships.
The airships carry a light armor on crew areas, ammo storages etc, but the whole envelope is not armored, but divided into many gasbags, like airships in real life were, so piercing a few of them won't bring the airship down. To clarify, these airships are rigid airships, not blimps.
Now, the question is: what weapons are best for airship to airship combat in such scenario?
I was thinking about simple thermobaric warheads for tearing apart envelope and gasbags, coupled with light cannons for precise strikes on ship's vital areas, like engines, armament etc. What do you think? Edit: Some notes on tech level: military tech is similar to what we had on Earth post-ww1 but planes are significantly less advanced than in our world, they are similar to planes that took part in the beginning fights of First World War, and are sometimes used as deck planes for airships. Material tech is more advanced, and makes it possible to build durable drigibles.