A charity air ambulance was grounded after youths attacked it as it attended an emergency call to an injured baby.
Witnesses said they saw two teenagers hanging off the tail fin and swinging on the pilot's door of the Kent Air Ambulance helicopter after it landed in a field near Vine Cricket Ground in Sevenoaks at around 4.30pm on Sunday.
When the pilot asked them to stop, they became verbally aggressive and one of the youths grabbed the pilot around the throat, a spokeswoman for Kent Police said.
The attack prevented the helicopter from being used to airlift the baby, meaning that it had to be taken to hospital by road accompanied by the air ambulance's crew.
The aircraft was then grounded for a day so it could be given a full inspection by an engineer to check for any damage.
Kent Air Ambulance chief executive John Tickner said: "I find it incredulous that anybody would want to attack a charity air ambulance and its crew, whose sole purpose is to help seriously injured people in their time of need.
"It is completely unacceptable that any of our staff are subjected to an assault and we will always fully support the police in any further action."
The police spokeswoman said a 19-year-old man was arrested on suspicion of criminal damage and public order offences while a 17-year-old boy was arrested on suspicion of common assault and public order offences.
They have both since been released on bail while inquiries continue.
Pc John Boyden added: "It is difficult to understand this sort of mindless behaviour.
"Why anyone would want to damage and abuse a service that provides a lifeline to people of Kent is beyond comprehension.
"It's been suggested that alcohol played a part in this incident but that is no excuse and the Sevenoaks neighbourhood policing team will be increasing patrols in the area and dealing with any such drink-related nuisance and anti-social behaviour robustly."Reuse content