No-frills airline EasyJet has agreed to be taken over in a £5.7bn deal by US firm Apollo after a rival bidder dropped out.

The takeover was agreed after US investment firm Castlelake, which had made a series of offers for the carrier, said it was withdrawing from the bid battle.

EasyJet is one of Europe’s largest airlines. It employs more than 19,000 people, and flies around 1,200 routes across 35 European countries.

It was founded by Sir Stelios Haji-Ioannou in 1995 to offer cheap air fares to Europe from the UK.

Its first flights took off in November 1995 flying from Luton to Glasgow and Edinburgh, with its first international flights the following year.

Sir Stelios and his family still own around 15% of the business, and he said he supported Apollo’s plans for the airline “to create more growth”.

“My family and I intend to remain invested as long-term major shareholders of EasyJet for the next chapter in the company’s journey,” he said in a statement.

The future ownership of EasyJet has been uncertain since it emerged in late May that Castlelake was considering a bid for the airline.

Castlelake made a number of approaches for EasyJet, which were rebuffed initially after the carrier accused the US firm of trying to buy it “on the cheap”.

In early July, EasyJet and Castlelake said they had agreed a deal in principle, but then Apollo – which owns Wagamama parent The Restaurant Group – swooped in with a higher bid.

Under the offer from Apollo, EasyJet shareholders will receive £7.15 per share.

Apollo said it was “highly supportive” of the airline’s existing strategy, adding there was “a significant opportunity to accelerate the operational and commercial ambitions” for the EasyJet Group.

“EasyJet is a leader in European aviation, having built a differentiated market position through its compelling customer proposition, expansive network and strong brand,” said Alex van Hoek, partner and European private equity lead at Apollo.

EasyJet chief executive Kenton Jarvis said “We welcome Apollo’s commitment to our business and our people, and believe that its experience in the aviation sector makes it a strong partner for EasyJet.”