The airport has submitted plans to increase its capacity by the late 2030s.
Vegan pizza restaurant Purezza had been transporting white powder in a suitcase when a member of staff was stopped by the police.
Gatwick has apologised to passengers at the UK’s second busiest airport.
The sickness was "mainly a bad chesty cough, possibly chest infection", a passenger said.
The group has booked £10m in extra costs and £5m in lost revenues from the incident in December.
Departures at Heathrow were suspended for an hour on Tuesday night due to a drone sighting.
More than 140,000 passengers were affected by about 1,000 cancellations and delays during 36 hours of chaos at the airport.
The airport is the eighth-busiest in Europe.
The couple quizzed by police over the drone disruption at Gatwick Airport say they feel "completely violated" by the experience.
What support passengers might get and who they should contact.