AER LINGUS will outline aggressive plans to expand its short-haul routes as a central part of its defence against the hostile €1.48 billion takeover bid by Ryanair. The airline will try to convince investors that it can grow its revenues rapidly and rein in costs without Ryanair.

The flag carrier, in which Ryanair has built up a 19.2% stake, will unveil a lengthy defence document in eight days’ time.

Aer Lingus’s short-haul strategy is to focus on increasing the frequency of flights to a number of its existing destinations, rather than unveiling new locations.

“This would be more profitable, as we would be upping the productivity of existing staff,” said a source. The document is also expected to highlight how the group aims to grow its ancillary revenues.

The fresh focus on costs was outlined by Dermot Mannion, the airline’s chief executive, to union officials on Wednesday. Michael O’Leary, Ryanair’s chief executive, has warned Aer Lingus’s 3,475 employees that there will be significant job losses if it acquires the former state-owned company.

He has identified the airline’s catering section, sales and marketing in America and clerical jobs in Dublin as likely targets for cuts.

Aer Lingus and its corporate advisers, AIB Capital Markets, Goldman Sachs and Merrion Capital, will also highlight competition issues in the document. It will again take issue with Ryanair’s claims that members of the employee share ownership trust (Esot), which has a 12.6% stake in the airline, stand to receive an average payment of €60,000 if the Esot takes up the offer.

Aer Lingus said the Esot’s membership — which is made up of about 4,665 people — and existing borrowings mean the offer is worth an average of about €32,500 per member.

O’Leary has already conceded that his €2.80-a-share bid is unlikely to succeed without the backing of the Esot, which is currently part of a loose alliance of shareholders, along with the government, pilots and the businessman Denis O’Brien, opposing the bid.

This group of shareholders, which claims that it is not acting in concert, currently holds about 46% of stock.