Aurigny will provide ground handling for the lifeline route using its Gatwick-based staff and equipment.
The recent collapse of both Eastern Airways and Blue Islands has sent shockwaves through the UK's regional airline industry.
While Aurigny and Loganair are filling the void left by Blue Islands, Skybus has successfully bid to operate Newquay Cornwall to Gatwick.
This is a lifeline route and is subsidised by Cornwall Council, exactly as the States of Guernsey provides money to cover the Alderney routes whcih are also run under a PSO, or Public Service Obligation.
With Aurigny using Skybus to operate its Alderney services, it in turn is providing ground handling for Skybus at Gatwick, on strictly commercial terms.
Aurigny has both staff and its own airside equipment at London's second hub.
Aurigny stress that the arrangement will not involve leasing Skybus any of its ATR fleet.
But, the deal will give Aurigny access to a leased aircraft over the busy Christmas period, should it need the back up.
The first flight, using an Ascend Airways Boeing 737-800, took off from Cornwall on Sunday, 23 November.
Separately, Guernsey's Economic Development Committee has confirmed that BA will receive a subsidy and route incentive discounts on its new Heathrow service, due to begin in April next year.
The Committee says the package will cover multiple years.
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