At least 12 inbound flights were diverted away from Gatwick for almost an hour while an investigation took place into the suspected drone.
One departing passenger, Tarquin Cooper, tweeted: “Are you aware Gatwick is closed due to drone activity? Been sitting on tarmac for last hour.”
Seven easyJet arrivals were diverted – five to Luton, one to Southend and another to Bristol.
British Airways’ arrivals from Faro and Palma touched down instead at Stansted. The Essex airport was also the unexpected destination for passengers flying on Vueling from Rome, Tui from Kavala and Turkish Airlines from Istanbul.
A Gatwick spokesperson said: “Passenger safety is the airport’s absolute priority and – following established procedures – operations at London Gatwick were suspended temporarily at 1.44pm while investigations into the sighting of a suspected drone close to the airfield took place.
“These investigations have now [been] completed and the airfield reopened at 2.35pm.
London Planespotting captured moment a number of silver balloons released very close to the airport.