Low-cost airline Jet2.com is to open its first base in the south of England at Stansted.
The Essex airport will be the carrier's ninth UK base when services begin on March 29 next year.
The airline's chief executive Steve Heapy said the move would make it "a truly national brand".
Jet2.com will serve 21 European leisure destinations from Stansted, including daily flights to Alicante, Faro, Ibiza, Malaga and Majorca.
This will put the airline on a par with easyJet as the second largest carrier at the airport, behind Ryanair.
The flights will operate using six new Boeing 737-800 aircraft, with the majority during quieter periods at the airport to fill gaps in its schedule and make use of its spare runway capacity.
Customers of the airline's package holiday arm, Jet2holidays, will also use the new routes.
Mr Heapy told the Press Association: "Because of our family friendly ethos, Jet2.com and Jet2holidays have enjoyed years of success and growth in northern England, Scotland and Northern Ireland.
"We think that we have a product that people in the south of England and the east of England want.
"We're offering routes from London Stansted Airport which we think are under-served.
"We're offering a flight only product and also our package holiday product, which we think is definitely under-served from Stansted Airport."
Mr Heapy expects the firm's package holidays from Stansted to be "a huge draw for people" due to features such as convenient flight times, a deposit of just £60 per person and being Atol protected.
"We provide the best quality of customer service in the country," he added. "On our flights every customer is a VIP."
Stansted's chief executive Andrew Cowan described the announcement as a "vote of confidence in Stansted" and said it demonstrated the airport's ability to offer more flights amid the long-delayed decision on whether to boost runway capacity at Heathrow or Gatwick.
He said: "We've said all along that better use should be made of existing capacity. Our runway is just over half full.
"Irrespective of what decisions are made around new runways, nothing is going to be built for at least another 10 to 15 years.
"We're very well placed to soak up that existing demand during that period."
Jet2.com's arrival at Stansted is expected to create 250 new jobs at the airport and support more jobs across the region.
The airline is marking the launch by offering 50,000 flights for £30.