Tyvak is a cool material that priority mail envelopes (which are free) are made out of. It is a mixture of paper and cotton and you can cut it, color it, stitch it, glue it and best of all its super strong, water resistant and lightweight; if you are not in the States you might want to check out an office supply store if your Post Office does not keep such and envelope.
You will need:
Priority Mail envelope
2 wooden skewers or straws
Kite string or fine nylon string
Colored Pens (If you want to decorate)
Cut open your envelope carefully down the backside seam and across the bottom, remove the flap. You should be able to open it up as shown below.
Fold in half and fold corner back to seam, unfold.
Now cut along the fold you just made and also from the corner you just cut to the bottom seam.
At this point you can also cut a shape into the bottom half of your kite if you choose, it helps it fly the correct way up. When you open up the envelope again it up it should look like this,
Now we tape the 2 skewers into the folds on the outer side of the main body of the kite. Tape the full length of the skewer.
Now in the tip of each triangle punch a hole through which we will thread the string.
Once you have threaded between the two holes attach the kite string to the center of the tied thread.
I then rolled a length of string around a wooden peg to go outside with, this just made it easier for the boys to hold onto.
Now lets go fly a kite...
The boys had the best time, luckily it was a windy day. I was able to stand still to fly the kite (not whilst also taking pictures). However, the boys technique involved running as fast as possible around our yard while the kites flew out behind them; this also seemed to keep the kites up!
We were out there for ages despite this cold April day, the boys were exhausted. But as you see in the pictures my poor yard is so in need of warm weather to turn green again.
All in all a fun project that is practically free and as Mary Poppins sings,
"All you need is paper and string and you'll have your own set of wings."