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.
More top news
Diners at a Norfolk pub last night had a lucky escape after a car ploughed through the wall as they ate
Isolated showers clearing. Drier on Sunday, brightest in the west.
Up to 20,000 people are expected to visit the first Duxford air show since the Shoreham disaster on the South coast.