I was a mechanic for a Life Flight. The biggest difference between an ambulance and a life flight is that there are only paramedics on an ambulance. The helicopters have a 3 person crew...The pilot, An RN and a Paramedic. Along with the RN on the helicopter, comes the life saving equipment and narcotics that only an RN can administer. Another thing to consider is if if St. Mary's is a "Level 1" Trauma Center. If a patient "crashes" in route, a helicopter can divert much easier and faster than an ambulance.