If you have limited room in your luggage and you're on a budget, you might want to make a lap box to use in place of an easel. Here's how:
1. Purchase a plastic project case. They cost a few bucks at an office supply store. The case should be large enough to hold your canvas attached to cardboard or your canvas panel, plus your plastic or paper palette, flat on the inside. My box is large enough for 9 x 12.
2. Spray paint the entire inside of the box black. This will shade your painting and palette from direct sunlight if you sit with the box facing toward the sun.
3. With a small drill or a nail, make holes 3 or 4 inches from the hinge, on both sides of the top and the bottom of the box. Feed a string through the holes, and tie it so that the string holds the lid of the box up, at just a little more than 90 degrees. (If it is less, the box will close on you when you don't want it to.)
4. Get a piece of plexiglass that fits in the bottom of the box. Spray paint the back side of it gray.
6. Place your palette in the bottom of the box. Clip the canvas on cardboard or the panel to the top with clips that you can get at a hardware store. You can also carry a bungee cord, which is useful for fastening the lap box to picnic benches, etc. This box weighs 1.6 lbs with a single canvas and cardboard.
8. The watercolor version can be made without the string hinge, so your paper can lie flat. If you wish, you can hot-glue your watercolor palette into the bottom of the box. This box weighs 1.3 lbs.