Originally Posted by Jumbodriver

All of the A320 series have winglets (except some early A320-100s). It's only since around 2012 (I think) that they've been built with the ability to fit sharklets without major modifications to the wing. That's why it's the more recent A320s that BA has had fitted with them, it's a 1 day job. The older ones would take over a month. I think the A318s are too old for the easy fit.