Can you imagine the havoc Derpy joining the wonderbolts would cause? I bet Fluttershy is a silent aerobatic god though. Just give her a reason and she'd be doing loops around Rainbow Dash.
Argos and Target are both carrying an exclusive set of Wonderbolts brushables. Head on down below the break for them!
My Little Pony Wonderbolts 6in Collection Pack
My Little Pony Wonderbolts 3in 2 Pack.
Thanks to Keira for the heads up!