LONDON - Wizz Air vowed on Thursday to ride out the coronavirus crisis and emerge stronger, after the ultra-low cost airline swung to a 115 million-euro ($139 million) quarterly loss.

As most airlines cut fleets and networks, Hungary-based Wizz has been adding new bases and aircraft in an attempt to grab a bigger share of the post-pandemic market.

Revenue fell 77% to 149.9 million euros on a 77% drop in passengers in its third quarter ended Dec. 30, but Wizz said its 1.2 billion cash could withstand another two years of slump.

While Wizz is "not immune" to the short-term industry pain, Chief Executive Jozsef Varadi told Reuters, "the longer it goes, the better we will emerge" in competitive terms.

"In a way, ironically, a longer crisis would benefit Wizz Air more," he said.

London-listed Wizz and budget rival easyJet posted quarterly numbers just as travel recovery hopes are hit by new setbacks. Despite progress on vaccination rollouts, governments are imposing tighter restrictions to contain the spread of more infectious COVID-19 variants. 

Wizz shares were 0.3% higher in London trading, while easyJet was down 2.4%, leading most of the European airline sector lower after its quarterly revenue fell 88% to 165 million pounds ($225 million).

Demand will remain weak at least through the first three months of 2021, Wizz Air said. Beyond that, Varadi voiced optimism that some level of summer demand could be salvaged.

"People will want to get away from cities," he said, and Wizz is primed to ramp up "sea and sun" flights with as little as three weeks' notice.

Wizz, which vies with larger peer Ryanair for the title of Europe's lowest-cost operator, said it expected 2021 to be a "transition year out of the Covid-19 crisis", but gave no financial guidance.

Wizz earlier this month raised 500 million euros in a bond sale with an yield of just 1.35% reflecting its investment-grade rating, a rarity among airlines. 

($1 = 0.8268 euros)

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(Reporting by Laurence Frost in Paris and Paul Sandle in London; Additional reporting by Sarah Young; Editing by James Davey, Costas Pitas and Jane Merriman) ((paul.sandle@thomsonreuters.com; +44 20 7542 6843; Reuters Messaging: paul.sandle.thomsonreuters.com@reuters.net))