A negative is that it is a lot harder to check-out the vehicle when it is attached to an airplane than when it is on the ground. Also, on the ground the success

A negative is that it is a lot harder to check-out the vehicle when it is attached to an airplane than when it is on the ground. Also, on the ground the successful start-up of all the engines can be verified before the vehicle is released. If one engine fails to start, the rest can be shutdown with the vehicle still intact on the ground. But, when an air-launching, there is no going back once the vehicle is dropped.