All flights at Birmingham Airport have been suspended and the runway closed after it was believed a small aircraft crashed near the site.
Two casualties were reported in the incident, West Midlands Police said.
Eyewitnesses described smoke coming from a light aircraft at the end of the runway just after 1530 GMT.
A Birmingham Airport spokesman said the aircraft involved was a private Cessna and all flights were currently suspended.
"The incident occurred on arrival into the airport and the emergency services are in attendance.
"The airport is currently closed."
"If you are due to travel to the airport this evening, please contact your airline for further guidance and do not come to the airport at this time."
Manchester Airport and East Midlands Airport said they were taking diverted flights from Birmingham.