Aer Arann is seeking up to 100 redundancies as part of a cost reduction programme.
The airline says it wants to concentrate more on charter flights and leasing its aircraft and crews to other airlines.
It says key routes will remain unaffected but the company is changing its business model to ensure its long term future.
A spokesman said the 100 redundancies is a worst case scenario - it would represent a reduction in staff numbers of around 25%.
Currently, the airline operates 12 aircraft on scheduled services and one plane on lease.
Aer Arann operates over 600 flights per week, across 40 routes in Ireland to the UK and northern France, as well as Amsterdam.
Passenger numbers have grown from 12,000 in its first year to 1.1m in 2006.
Separately, management at one of the largest private sector employers in the south-east is to meet with union representatives tomorrow to discuss possible cost-cutting measures.
Bausch and Lomb employs 1,400 people at its manufacturing facility at the IDA industrial estate in Waterford city.
It is understood that job losses are not part of proposed cost cutting measures,
Up to two years ago, the company employed 1,800 people but most temporary employees have not had their contracts renewed in the past year.
The company makes eye-care products.
