AER Lingus says it is "at a loss" as to why it has been served with notice of industrial action by unions.
The carrier said it had "comprehensively and sustainably" addressed pension provision entitlements for staff following negotiations over a €700m-plus deficit at the Irish Airlines Superannuation Scheme (IASS).
Talks aimed at resolving the massive pension hole broke down last week at the Labour Relations Commission.
A failure to address the huge deficit would mean thousands of workers paying money into the scheme would see their future pension entitlements severely cut.
SIPTU has claimed that Aer Lingus has failed to put forward "any meaningful initiatives" to remedy the deficit.
Aer Lingus staff have said they'll stop work for two hours on November 19.