The Lydd Airport Action Group has been campaigning against the expansion of the airport.
Louise Barton told ITV News it would continue to fight the plans and expected the proposal now to be embroiled in years of legal wrangling.
"The whole nuclear safety argument has been completed disregarded," she said.
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Any lingering showers clearing into tonight with a mostly dry but chilly night ahead. A cool but sunny start to Sunday.
Further heavy showers gradually clearing away this evening. Dry but chilly tonight, then dry with plenty of sunshine tomorrow.
Heavy showers turning potentially thundery this afternoon. Becoming dry but chilly tonight, then dry and sunny tomorrow.