The runway at Teesside Airport has been closed after an incident involving a light aircraft left three people in hospital.
The airport said in a statement on Twitter that the incident occurred at 9.39am on Saturday and the pilot and two passengers on board needed emergency care.
It said its runway would remain closed “until further notice” while an investigation is carried out.
Rob Cherrie, general manager at County Durham and Darlington Fire and Rescue Service, told the PA news agency that the light aircraft “had taken off then come back down again very quickly”.
Mr Cherrie, who was incident commander at the scene, said: “I wouldn’t like to speculate on why that occurred.”
He said that fire crews had been forced to cut the three people out of the plane.
There were passengers at the airport waiting to board flights at the time of the crash.
“I wouldn’t say it’s the busiest airport but there were passengers present – by the time we went on to the runway it was closed and flights had been diverted up to Newcastle etc.”
The fire service sent two fire engines to the scene, while two of the airport’s own appliances had been part of the response, Mr Cherrie said.
Teesside Airport said: “We can confirm an incident occurred today involving a light aircraft at 9.39am. A pilot and two passengers were onboard and have been taken to hospital.
“Our runway will remain closed until further notice while a thorough investigation is carried out.
“We would like to thank the emergency services (and) on-site staff for their quick response.”
In a message to passengers due to travel on outbound Ryanair flights, it said: “Arrangements have been made for all passengers to be coached to Newcastle Airport where the flight will depart.
“Please note, you must check-in for your flight at Teesside.
“We’d like to thank you for your patience and cooperation.”
The North Eastern Ambulance Service (NEAS) said one of the three casualties had suffered serious injuries.
NEAS said in a statement: “We were called at 9.35am to reports of a light aircraft crashing at Durham Tees Valley Airport.
“We sent two ambulances, a specialist paramedic, an officer and requested support from the Great North Air Ambulance.
“In total, three patients were taken to James Cook hospital, one with serious injuries. One patient was taken by air and the two other patients were transported by road.”
Tees Valley mayor Ben Houchen tweeted: “Thoughts and prayers are with the three people onboard at the time of the incident and their families.
“At this time I want to thank the incredible response by the airport fire service and the immediate response of local emergency services to the incident.”
The Air Accident Investigation Branch said: “An accident at Teesside International Airport involving a light aircraft has been notified to the AAIB.
“An investigation has been launched and a multidisciplinary team of inspectors are on their way to the accident site.”