Rotary is not too slow - these transfers are never emergencies in the medical sense although they may be urgent. Minutes do not matter and we work hard to prevent rushing. However beyond a certain distance the cost and (almost) door to door transfer of rotary is balanced by fixed wing. We have been operating both for almost thirty years.
Sadly military aircraft are not ideal. They may be free to the NHS at point of use, they may fly when civilian aircraft cannot, and they may be big, BUT vibration levels are physiologically damaging to sedated patients, noise levels make monitoring more difficult. The lack of fixed equipment results in problems with security, power and gas provision plus in practical terms a less comprehensive module. The medical teams can never have the familiarity and experience of the airframe that they do with their own aircraft and it remains a hotch pitch
The SAR posters will attempt to shoot me down, telling me how many 'successful' transfers they have undertaken, but the level of medical care will always be compromised. This country should have dedicated ITU inter hospital transfer systems. We don't use tanks instead of ground ambulances and nor should we use SAR because the state refuses to meet its responsibilities. We undertook such transfers for almost 20 years but the NHS repeatedly refused to pay