Figures from the firm show that while Gatwick would be boosted by more than 5,000 jobs even without expansion, the airport could generate dramatically more jobs with a new runway.
New roles would primarily be generated within airline businesses, which would put on up to 14,500 jobs, while service suppliers, contractors and retailers could all take on between 3,000 and 4,500 staff over the next 35 years.
Gatwick chief executive Stewart Wingate said: “Gatwick’s second runway will not only connect the UK to existing and emerging markets around the world, it will also provide thousands of jobs across the South East and deliver a once in a generation opportunity for young people to directly benefit from expansion.
“This is an example of how Gatwick expansion is a nationally-significant project and can provide a positive boost to the local area, to the region, and to the UK as a whole.”
The firm says Gatwick already supports more than 20,000 jobs directly and a further 10,000 jobs indirectly, and that it can acts boosting wages across the local economy.
New jobs would come in addition to a £3.75m apprenticeship fund Gatwick has already pledged to establish if it is given the green light.
The fund would create 2,500 opportunities, providing grants of £1,500 to cover the start-up costs of each new apprenticeship.
Just days after the UK voted to leave the EU, former transport secretary Patrick McLoughlin announced an expansion decision would not be made until “at least October”
The decision had already been delayed to this summer, as the government waited for further data on the environmental impact of expansion.
The Davies Commission called for a third runway at Heathrow last July.
A Yougov poll of MPs last week revealed that 74 per cent think a third runway at Heathrow would demonstrate that the UK wants to trade internationally, compared to only 12 per cent who said the same of an expanded Gatwick.