This study compared a hospital-based aeromedical program to a ground paramedic service in order to determine whether the element of prehospital time or prehospital care is the major contributor towards improved survival. One hundred twenty-six severe blunt trauma patients were studied. There were 93(73.81%) transported by air and 33(26.19%) transported by ground. Utilizing the TRISS methodology, the air patients had a probability of survival of 2.23 SD better than the national norm, and the ground patients had a -2.69 SD below the national norm. The air patients had a higher percentage of intubated patients (42% vs 3%) and use of PASG(56% vs 30%). There was no significant difference in the prehospital times of either the air or ground services once they had arrived at the scene. Since the scene time of both services is similar, the improved survival of the air patients may be due to the technical intervention procedures performed.