Hey Kamil, how's it going? Hope you're well. A 'drive' is like a big push to try and achieve something e.g. a hospital might hold a 'blood drive' to try and get people to donate blood, or a homeless charity might hold a 'food drive' to ask the public for donations. 'Mounted' in this context means 'began' or 'launched', so put them together and it basically says "Ryanair, which has started to make a big effort to recognise unions..." Hope this helps!

In this context, they Ryanair have started some form of initiative related to unions. Another way is that they are seriously considering recognising unions. I hope this helps!

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