A plane carrying 25 people came off the runway after landing, forcing the suspension of flights in and out of Bristol Airport.
The Embraer 145 aircraft, from Frankfurt, left the runway as it taxied to the terminal just after 11:30 GMT.
"No-one was hurt and passengers were disembarked and returned to the terminal by coach," a spokesman said.
Currently, 45 arriving flights and 28 departures have been cancelled or diverted to other airports.
Bristol Airport is telling passengers via Twitter the runway is unlikely to reopen until at least 21:00 GMT.
The Air Accidents Investigation Branch (AAIB) confirmed it was sending a team to the airport.
Passengers on EasyJet flights to Inverness, Prague, Belfast and Geneva were told to collect their bags and make alternative flight arrangements "from home".
Other airlines affected include Ryanair, Aurigny, Aer Lingus, KLM, BMI Regional, Flybe, Thomas Cook, and TUI.
Airline operator BMI tweeted that its flight BM1822 from Frankfurt was the plane affected.
"All 22 passengers and three crew aboard the Embraer 145 jet disembarked safely with no reported injuries. Emergency services attended as a precaution," the airline spokesman said.
What the airlines are advising:
- EasyJet is telling customers via Twitter that the runway "is due to open at 1800"
- Ryanair is advising travellers to contact a member of airport staff "who will be able to provide updates"
- Aurigny said customers are being kept updated by text message
- BMI Regional is advising passengers to contact Bristol Airport
The airport said the runway would remain closed while investigations begin, the plane is towed away and debris cleared.
"We're unable to confirm a time that the runway will reopen at this time," a spokesman said.
"While it is too early to speculate about the cause of the incident, we are confident that it was not related to the low visibility conditions currently being experienced."
The airport said additional staff were being brought in to assist passengers.
At the scene: Andrew Segal, BBC News
Passengers were told at 12:30 GMT that all flights inbound and outbound were suspended due to "an incident", although they were not initially told the nature of it.
Rumours soon started about a plane coming off a runway, which was later confirmed by airport staff – who stressed no-one was hurt.
People are staying calm in the terminal, although those who have had flights cancelled at this busy time are now having to decide whether to get alternative flights out today or tomorrow, or give up their plans for the festive trips onwards.
Dave Joyce, who was due to fly to Javea in Spain with his family, said his plane was diverted away from the airport.
The 53-year-old finance worker said: "Nothing's moving at the minute and we haven't had any information at all.
"People keep coming but nobody's leaving, so it's all getting pretty crowded just now.
"We've got seats in a restaurant, so we're OK, but my wife's mother is in a wheelchair.
"A great start to the Christmas break… Javea seems a long way away now."
Bristol Airport said more than 190,000 passengers were due to use the airport between 22 December and 1 January – a 5% increase on the same period last year.