Lofo 101, Hi.
I work for Ryanair mate, no layovers involved ever!
UK to Kos, 4 hours, southbound, sun on my left arm the whole way. 25 minute turnaround then return to UK. Northbound again sun on me the whole way.
About half way home I felt as if my arm was burning but discounted that as possible because in 15 years never experienced sunburn before.
Next morning left forearm sunburnt and back of left hand covered in heat rash pimples and also burnt! Irritation only reducing now.
I too thought the glass gave some protection and I'm sure it does. Has anyone else ever had this reaction?