Airline fares for the patient and the escort
The largest component. Escorts generally travel in the same cabin as the patient, and airlines often require the escort's fare in addition to the patient's. Business or premium cabins are sometimes required for a patient who cannot sit upright for long periods, which changes the number significantly.
Clinician time and travel
You are paying for the escort's time from the moment they leave base until they return, including the outbound positioning flight, waiting time, the journey itself and the return sector. A long-haul repatriation can occupy a clinician for several days.
Seat, stretcher or oxygen configuration
A seated escort is the cheapest arrangement. A commercial airline stretcher requires the carrier to block a block of seats and install their stretcher kit, which costs several fares. In-flight oxygen is supplied by the airline and charged separately on most carriers.
Airline medical clearance
Carriers require a medical information form completed by the treating doctor, reviewed by their own medical department. Clearance takes time and can be declined. That process is coordination work rather than a large cost, but it drives the timeline.
Ground transport and accommodation
Road ambulance or accessible transfer at both ends, plus any overnight accommodation needed where itineraries do not connect. Long routings with a layover add a night for the patient and the escort.
When an escort is not the right answer
If the patient needs ventilation, invasive monitoring, or is clinically unstable, no airline will clear the flight and an escort is not an option regardless of cost. In that case a dedicated air ambulance is the only safe route. That call belongs to the treating doctor.