Police were called to a confrontation between two British Airways passengers which was reportedly sparked by a Donald Trump hat.
The Metropolitan Police said two women – one aged in her 40s and another in her 60s – accused each other of affray at Heathrow Airport on Monday.
No arrests were made.
The Sun reported the row broke out in Terminal 5 when one of the women asked the other to remove a red baseball cap emblazoned with the US presidential candidate’s Make America Great Again slogan.
Punches were thrown after the request was refused, according to the newspaper.
The pair later boarded a plane bound for Austin, Texas, but the confrontation resumed and they were escorted off the aircraft by police, The Sun said.
Flight BA191 was scheduled to depart at 12.10pm but was delayed until 2.11pm.
A Metropolitan Police spokesperson said: “Shortly after 12.45pm on Monday, police at Heathrow were made aware of an incident involving two women waiting to board a plane in Terminal 5.
“A woman in her 40s and a woman in her 60s made counter allegations of affray. Inquiries are ongoing.”
A British Airways spokesperson said: “We apologised to our customers for the delay and got them on the way as quickly as possible.”