A 41-year-old man from France is being questioned after "what appears to be a firearm" was discovered in a bin at Gatwick airport, Sussex Police said.
The airport's North Terminal was evacuated following a subsequent security alert, but has now been re-opened.
Gatwick Airport says the North Terminal has been evacuated "due to an incident".
The airport said it was a "precautionary measure".
The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.