Here are the painting I did yesterday. Plein aire is a fancy artsy term meaning that it was painted outside in the plain air. You are painting from life. Whatever is right in front of you is what you are painting. It is tricky since you are limited to what supplies you want to carry, how long you want to stay there, the elements and the way the light changes as the sun moves. But I find it fun and don't do it as often as I would like.
These are watercolor sketches. I find watercolor easy to carry around and set up.