Great North Air Ambulance Service (GNAAS) will only carry critically ill patients on its helicopters amid the coronavirus outbreak, it has announced,
It said patients would also have to be on closed circuit ventilation in order to reduce the "risk of spreading infection within the aircraft".
Anyone less seriously ill will be transported to hospital by road.
The charity said the challenges being posed by the pandemic were "absolutely vast".
GNAAS said while it would continue to operate across the north-east of England and Yorkshire, and staff would still deliver blood transfusions and anaesthetic procedures to anyone who needs them, only the most severely injured would be airlifted to hospital.
Director of operations Andy Mawson said: "There is guidance from Public Health England that says air ambulances should not be used to transport [people with] possible or known cases of coronavirus.
"However, to determine that in the community is very difficult.
"What I would like to stress is at the moment that we aren't carrying patients routinely where we can avoid having to do so.
"What we are able to do is deliver our critical care teams to the patient's site anywhere in the region and have the option to transport that patient by road."
GNAAS said its teams, including pilots, were using personal protective equipment needed to operate safely and that it would monitor the situation "continuously".
It estimates it is losing more than £100,000 per month in donations following the cancellation of fundraising events.