Rollingthunder,
I've used Econokote exactly once, and only once. It was so bad that I actually threw away the unused portions that were left over. I wouldn't use it again even it I was payed to use it.

You should try to patch the hole correctly as mentioned above. If you really don't want to bother with doing it right you can just cover the hole with packing tape and fly the plane. It won't look very good, but it will fly. In fact, every flight box should have a roll of packing tape in it for quick repairs at the field.

Hope this helps

Ken