They've been credited with increasing the chances of surviving a serious injury by up to 20 percent.
But charities like the East Anglian Air Ambulance and Essex and Herts Air Ambulance receive no government funding, and rely entirely on donations to keep going.
Jonathan Wills and Elodie Harper spoke to Diana Jakubowska from the East Anglian Air Ambulance about how they manage to fund their work and keep flying.
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Teams searching for the missing RAF serviceman Corrie McKeague have admitted they're running out of logical places to look for him.
Cloud will thicken this evening but most places will remain dry. However some rain will creep in early Monday morning. Lows of 8 deg C.
Former Australia lock forward, who also played for Northampton and Cambridge University, dies aged 37