was just wondering about leather jackets, about what's the best leather... I think the most common is lambskin
Lambskin is certainly not the most common for flight jackets, or probably any leather considering it's lots more expensive. Traditionally, they are either horsehide or goatskin, mostly the latter in recent history, but cheap versions today are often made of cowhide. What's best is subject to lots of factors including quality and thickness, and the use to which it is to be put and how it is treated. Goatskin in these jackets has stood the test of time. It's durable and becomes very supple with use. I was given a lambskin A2 many years ago as a gift (also a Perrone jacket, but it was stolen) and it was more 'luxurious" feeling, but didn't seem as robust. <shrug>