The flying doctor service has been extended to cover rural areas across the whole of Scotland.
The Emergency Medical Retrieval Service (EMRS) originally operated in the Hebrides and down the west coast.
It has now increased to two teams, with the number of doctors rising from eight to 15, and will cost £2m a year to run.
Consultants and mobile lifesaving equipment can fly to patients who are critically ill in the small hospitals of Scotland's islands and remote areas.
The service uses ambulance service and Royal Navy helicopters as well as aircraft which fly from Glasgow.
In the two years since its launch it has dealt with hundreds of cases at rural general hospitals, community hospitals and at remote GP practices.
Health Secretary Nicola Sturgeon said the service had saved lives.
Dr Stephen Hearns, the lead consultant with the EMRS, told BBC Radio Scotland's Good Morning Scotland programme: "In terms of staffing resource this is the most highly equipped emergency medical retrieval service in the world.
"Each day we will have two consultants on duty and they're consultants from emergency medicine, anaesthetics or intensive care who are trained and equipped to work in the aircraft and to carry out lifesaving critical care and interventions in any environment."
Mr Hearns said seriously ill patients in remote areas such as Mull or Barra would be taken to a hospital with GP cover, but critical care for any emergency interventions may not be available.
"The Emergency Medical Retrieval Service essentially brings the emergency department and the intensive care unit to the patient by helicopter or plane," he added.
The Scottish government funding to set up the service means that health staff now undertake responsibilities with the EMRS as part of their job plans.
Among those who have benefited from the service is Kerry MacNeill, 52, from Islay, who suffered from chest pains.
She had been feeling unwell and ended up at a local hospital only to learn she was having a heart attack.
She was then flown by the emergency retrieval team to the Golden Jubilee Hospital in Glasgow to be treated by cardiologists.
Ms MacNeill said: "The emergency team is a godsend for people like me who live in rural areas and are far away from specialist hospitals.
"I am lucky to be here and if it was not for the emergency retrieval team, I might not have made it."
She added: "On the day that I was treated, the team received another two calls from the Argyll area. It really is a lifeline for rural communities."
David Stoddart, an emergency medicine consultant based at the Royal Alexandra Hospital in Paisley, is a founder member of the service and led the team that treated Mrs MacNeill.
He said that prior to the introduction of the EMRS, Ms MacNeill would possibly have been transferred by air ambulance to the mainland where she would have been assessed and then taken to a specialist unit.
He added: "The benefit of the EMRS is that the patient can be assessed by critical care specialists and paramedics at the referring centre.
"The team is able to put in place critical care interventions to optimise the patient's condition prior to taking them to the most appropriate specialist hospital.
"In Mrs MacNeill's case, she had had a heart attack and therefore was taken to the cardiac unit at the Golden Jubilee.
"There is no doubt that lives have been saved because the EMRS is available. Patients are treated more rapidly by specialist doctors and, as a result, their long-term recovery and quality of life is much improved."