The number of BA passengers at Gatwick is scheduled to rise from 7.6 million to 12 million a year, while cargo volumes are expected to double to 400,000 tonnes a year.
BA said, however, that most of the increase would be catered for by using larger jets rather than through a massive fleet expansion. The airline said the number of aircraft in operation at Gatwick would grow by 10 to 80 in the next decade.
The expansion will see a number of new routes added to BA's network as well as increased frequency on existing services. There will be more flights on Latin American routes this summer and eight new routes to destinations in eastern and central Europe, the Caribbean and the Middle East.
The extra jobs being created are part of BA's wider programme to increase its workforce by 7,500 to 70,000 over the next three years. Fifteen thousand extra staff are being taken on in areas such as customer service, cabin crew, flight deck and telesales. At the same time, about 7,500 jobs are being cut in operations ranging from ground-handling and engineering to check-in facilities.
BA has increased its capacity at Gatwick by 20 per cent in each of the past three years. In the past decade it has increased its staff at Gatwick five-fold to 10,000, tripled passenger numbers - including those flown on franchise airlines - and invested pounds 1bn in fleet modernisation. This year, older DC10s and Boeing 747-200 jets will be replaced with the latest Boeing 777s and 747-400s.
The expansion at Gatwick has been achieved by transferring a significant number of routes from the overcrowded Heathrow.
It comes as BA waits to hear whether its long-delayed alliance with American Airlines will finally be cleared to go ahead. The European Competition Commissioner, Karel Van Miert, is expected to announce formal conditions later this month for allowing the alliance to proceed.
BA has indicated that if it is forced to surrender more than 300 slots at Heathrow to its rival carriers as the price for approval, then it will walk away from the deal.
In his initial findings, Mr Van Miert called for the surrender of 350 slots. The UK's Office of Fair Trading only recommended that BA and American give up 168 slots, phased over a two-year period.
If the American alliance does not go ahead, it will cast a shadow over BA's global strategy and possibly over the future of its chief executive Bob Ayling, who has championed the deal.
Most of the other big US carriers are already involved in alliances with other European airlines. Moreover, none of the alternative tie-ups BA might contemplate would produce the same economies of scale or transatlantic dominance as the American deal.
The European Commision has objected to the deal on the grounds that it would give BA monopoly over up to 70 per cent of traffic on the busiest transatlantic routes. But BA argues that the "open skies" deal that will accompany the go-ahead for the alliance will mean more competition and lower fares.