Yes. There are insurances that are specific to air ambulance coverage. Here are links to a few of them:

Air Ambulance Card -Prepaid medical transportation

Isis - Insurance company offering air ambulance program

Medex - Insurance company with air ambulance coverage

MASA - Mexico Insurance Professionals

This is a sample of the services out there that offer different forms of air ambulance coverage. There are other available coverages out there, through travel agencies and credit cards.

Primary health insurance providers usually only pay to transport a patient to the closest hospital. If you are abroad and need to get home, theres a good chance that a normal insurance provider won't pay for it.