Low-cost airline easyJet has secured a new 10-year deal with Luton Airport which could see it double in size at the site from four to nine million passengers a year.
It said the expansion would also see 2,500 jobs created at the airport and in the surrounding region.
But chief executive Carolyn McCall said the pace of the growth was dependent on improvements to the site being approved, adding that Luton could make a "real and immediate" contribution to the need for more airport capacity.
Easyjet has 15 aircraft based at the site, its second largest base in the London area, and employs 1,600 staff locally. It says it plans to grow capacity by 20% over the next year.
The airline says it will do this by adding new business and leisure routes and increasing frequencies from some of its existing 39 routes.
The announcement comes a week after easyJet revealed it was set for a smaller-than-expected loss over the winter, after it benefited from improved revenue trends and benign weather.
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Dry with warm sunny spells for most after a cloudy start in some areas
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It may start cloudy near coasts but the sun should break through, especially in the West.