Welcome to the Flight Nurses Forum, everyone! Here is some basic information for those interested in the subject:
Air & Surface Transport Nurses Association This is like the ENA or AACN for flight nursing.

FlightWeb - For Air Medical Professionals

Remember, each company has a different set of requirements/qualifications. For a "general" helicopter transport company, most look for 3-5 years of critical care ED and/or ICU) experience. Also, must have ACLS, PALS (or equivalent), basic trauma course (BTLS, TNCC, PHTLS, ETC), sometimes NRP (depending on the patient population served). Some states require nurses to either have a paramedic cert or a specific pre-hospital nursing certification, but I don't think it is all that many. If truly interested, check with your state's BON for scope of practice, state EMS office for additional requirements and one of the flight companies (many have their own websites) for their qualifications. As far as experience, a good mix of high-acuity ED and varied ICU/CCU experience is ideal. Not necessarily easy to obtain. Most flight companies will provide additional training (flight safety, flight physiology, additional trauma classes, advance skills-as permitted by the state, etc).

Hope this is useful.

'Cat'