The planes will be flying at speeds of 70-80 miles an hour, possibly up to 100 mph.
The aircraft will only be two metres apart wingtip to wingtip and flying just 30 feet off the ground as they make their passes over the airstrip.
The two girls have been given instructions on how to signal to the pilots: Thumbs up and a big scream means they're enjoying themselves. Thumbs down if they want to stop.
And if the girls are feeling very comfortable they're hoping to attempt a 'superwoman' pose as well.