Irish Airline Pilots Pensions Limited has announced its acquisition of 300,000of the airline's shares at €2.92 per unit.
This brings the pilots share to 2.18%.
The news follows reports that Aer Lingus employees expressed unease at the prospect of Ryanair's boss Michael O'Leary gaining control of the former state-owned company.
Last week low-cost airline Ryanair launched an offer worth €1.48 bn to buy Aer Lingus revealing that it had acquired over 16% of the issued share capital of Aer Lingus.
Ryanair then made an all-cash offer of €2.80 per share for the issued share capital of Aer Lingus not already in the ownership of Ryanair.