When Larkin is speeding towards Lerner airfield, he is on th phone, then it cuts to a wider shot, now he doesn't have the phone up to his ear, it then cuts back to the close up. He now has the phone up to his ear again.
That is an easy one to explain. Larkin was dialing the other person he called during his trip. One call was to the base to get the local military bases phone number, the other call was to the military base to bring in reinforcements.