I have heard awesome things about greenline covers if u need a breathable cover. And u wouldn't have to worry about it leaking in car etc
Are they pul on the inside though? I have one nikky cover that works okay. Its just too small. I bought a medium and it barely fits over the red edge WH & theres no way its going over a prefold. Its made with woven cotton that the tread has been treated in something to make it water resistant. I have an IV organic cotton cover that I bought off FSOT, but it has a pul lining so it bothers the baby too. I was just given some beautiful wool that was treated in liquid lanolin and is working great though. I bet if I can find a more heavy duty fitted and invest in some liquid lanolin our diapers would be car worthy. It's just hard with the compression I think.