Regional airline Eastern Airways confirmed the Newquay to London Gatwick route will operate daily from 15 December.
The essential air link is in collaboration with the UK Government and Cornwall Council.
Flights will operate initially daily to help quickly restore connections before Christmas and the New Year.
It then increases to fourteen flights each way a week, operating double-daily round-trips timed to allow a full day in London or Cornwall.
The service will be operated by regional turbo-prop aircraft for a lower carbon environmentally sustainable option, the airline says.
Fares start from £34.99 one-way, including a complimentary 15kg hold bag and all taxes and charges.
Flights are available to book at www.easternairways.com.
Adam Wheatley, Managing Director at Eastern Airways, said: "We welcome the approach taken by all stakeholders and partners to commence this service and will continue to further support the South-West region in wider accessibility, adding around 20 new direct jobs at Cornwall Newquay Airport."
Eastern Airways already serves Cornwall Airport Newquay from Leeds-Bradford commencing services to the Cornish hub two years ago.
The airline serves UK and international airports including Dublin, Jersey, Gibraltar, Nantes, Paris, Rennes, Southampton, Sumburgh and Teesside Airports.
