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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Becoming clear and frosty overnight. Bright and dry on Monday.
An Essex councillor is appealing for help to find out what happened to her "beautiful, much-adored" daughter after she was found dead.
Frost and freezing fog overnight but milder with some rain tomorrow.