Stobart Air, which operates the Aer Lingus regional service, has said it is to reduce its workforce.
The company is to close its London Southend base and cut the number of staff it employs in Dublin and Cork.
Stobart Air did not say how many staff could potentially lose their jobs, but it is understood it could be up to 130.
Around 39 pilots and cabin crew may be made redundant in Dublin, 24 in Cork, with the balance of the cuts in London, Southend.
"The impact of Covid-19 has had a unprecedented impact on our airline and the aviation industry globally," it said in a statement.
"Over the course of the past three months, due to government restrictions, we have operated less than 5% of our normal schedule per month."
The company said it will restart services on a phased basis from 14 July with a reduced schedule.
This will involve it flying less aircraft and fewer flights as passenger numbers remain lower.
"As a result, a reduction in our workforce is required, in line with our reduced operating schedule," it said.
"While a difficult decision to take, it is a necessary one."
A consultation process has begun with staff and unions.
"While extremely regrettable, we need to align our resources with our operations and reduce costs across the business to allow the airline to operate sustainably," it said.