Stansted Airport was forced to briefly close its runway on Tuesday evening as police dealt with an incident involving protesters who had surrounded a parked plane.
Activists said they were attempting to keep a "deportation flight" used to remove failed asylum seekers grounded at the Essex airport.
A spokesman for the airport told The Independent takeoffs and landings were temporarily stopped "as a precaution" to allow police to check no protesters had made it onto the runway.
Several flights had to be diverted during the incident and aircraft were shown on flight radar apps having to circle near the airport.
Flights resumed late on Tuesday evening.
A statement from the activists said eight protesters from End Deportations, Lesbians and Gays Support the Migrants and Plane Stupid had surrounded the plane.
It said their target was a "mass deportation ’charter flight’ to Nigeria and Ghana".
A Facebook page called ‘Stop Charter Flights – End Deportations’ broadcast live from the protest.
Susan James, from Plane Stupid, said: “Mass deportations like the one we stopped tonight are immoral, unfair and illegal.
"I don’t want to stay silent in the face of mass deportations that are deliberately rushed and secretive.
“In the wake of the Brexit vote, this government is more keen than ever to be seen to be 'tough' on immigration.
"But its mass deportations have devastating human consequences. Everything about these deportations points to the fact that they are inhuman, and must be stopped."
One woman who the activists said was on the flight was quoted as saying: “My ex-husband said he knows I am being deported. He is waiting for me. He is planning to kill me. If he kills me- who will I look after my children?”
Another male deportee was quoted as saying: “I have been in this country for almost 18 years. My family and my life is here in the UK. If they take me back to Ghana I will kill myself.”
The Home Office refused to comment on the scheduled flight from Stansted but said deportations were an "essential element" of an "effective immigration system".
An airport spokesman earlier said: “There are a number of protesters on the north side of the airport away from the passenger terminal, away from the commercial side of the airport, where the private terminals are.
“We understand there is a protest around an aircraft, but we don’t have details of the plane.
“As a precaution flights have been suspended while police carry out an inspection.
“Essex Police believe they have contained all the people involved in the protest but as a precaution they are doing a double check.
“Once they have done that they will give the all clear to air traffic control.”