It is so soft and comfortable... perfect for flying!
WAIT!!! GO OUTSIDE!!! NO FLYING IN THE HOUSE!!!!!
Some Tips & Tricks:
I used a men's medium shirt in these pictures. I think it would fit most kids aged 2 - 10.
An XXL shirt works just as well, it will be fuller and can be made a little longer.
If it is going to be worn a lot, I recommend using elastic in the waist.
A t-shirt that doesn't have seams on the sides works best.
The bottom of the skirt will tend to roll up a little bit. If you're going for the jagged look, don't be shy, you can cut it pretty severely.
Big men's t-shirts are available in many colors at most thrift stores for around one dollar.
Use the sleeves of the t-shirt in exactly the same way to make a matching doll skirt!
You can see some more costume ideas in the "Dress-up" category.