A while ago I was thinking about getting a leather jacket made from Aero and upon receiving a leather sample called 'seal' I sent them an email regarding treatment of animals. This was there reply
"The leathers come from Cows, Horses and sheep..
The cows and sheep are used for food products and the skins are a by-product
The horse skins we use are from horses that die of natural causes only..
We don't use skins of animals that have solely been used for leather
We don't use ANY endangered species and wouldn't make anything for anyone
even if they approached us with this..
Seal is just a colour, the leather is dyed.."
I dislike leathers from animals killed purely for their hide and when we wear them we create an environment for demand so I try my best to have nothing to do with them (although i suppose one could also argue how well you wear the leather, I think most exotic leathers are a bit of a turn off personally.)
I think recycled or vintage leather products are definately okay. Alot of fair trade stores also sell "No Kill" leather products like these.