The West Sussex airport experienced a 61.3% fall in revenue and a £321m loss between January and June, compared with the same period in 2019. The prediction comes two days after it announced 600 jobs cuts following an 80% fall in passenger numbers. Chief executive Stewart Wingate said Covid-19 had had a "dramatic" impact.
The company's half-yearly results, published earlier, found earnings before tax and interest plummeted by 98.3%.
Passenger numbers fell from 22.2m to 7.5m over the same period.
In the statement, the airport said the restructuring plan would "better align the business to passenger and air traffic forecasts".
Mr Wingate said there were "small signs" of recovery, however.
He added: "As with any responsible company we have protected our financial resilience by significantly reducing our operational costs and capital expenditure."
He thanked staff for their hard work "whilst we go through this difficult time", and said he remained "optimistic that Gatwick will recover and retain its position as one of the UK's leading travel hubs".