From what I was reading, they put a big importance on cultural awareness etc. when recruiting staff. For this reason I was wondering would it give me any advantage to include religion on my initial application? I’m leaning towards not putting it in, but specifying either in the application or at the interview that I’m knowledgable.

I’m Muslim, but they wouldn’t guess that otherwise based on my name and nationality. I’m not sure if I should put it down, I can see that being either negative or positive. They might take it as a bonus for understanding the culture, but also it could be negative if they’d be worried I would want to wear hijab etc later (I don’t). If I didn’t put that could I specify that I’m knowledgable about Arab cultures etc?

If I didn’t mention it, would it be okay to mention at interview? Even just mentioning my knowledge (because I know for example, certain flights organise meals to coincide with breaking Ramadan fasts etc).

Also regardless of that, I took standard Arabic classes in university for six months. I’m by no means fluent, or even advanced in speaking it, but would it be a bonus to add that I have some basic knowledge of it? I could order food, discuss family, my neighbourhood, university/work etc, just the basics. And if I included that, would I specify I’d be willing to learn more?

I studied languages in univeristy, so I’m fluent in four languages (including English), I’m not going to add other languages I have a basic/intermediate knowledge in, but specifically because I’m applying to airlines based in the Middle East, I’m thinking it’d be worth noting I have even basic Arabic.

You could by all means put these things on your CV but I don't think it will be advantage. Yes, cultural awareness is important but it's more about being able to work well with other people no matter what religion or nationality. Any languages are advantageous but mostly the airlines only take fluency into account for reading the announcements and of course, the language used onboard will be English. If you state your religion, they might ask you if you are willing to serve alcohol, for example.