Some jobs will be lost at BMI following its acquisition according the International Airlines Group's Chief Executive, Willie Walsh.
Speaking on Morning Ireland, Mr Walsh said BMI's business is not sustainable in its current form and would need to be restructured, though the IAG acquisition still faces regulatory hurdles.
He says that once the transaction is complete, then the issue of restructuring will be addressed.
BMI currently operates flights from Dublin Airport while its low-cost subsidiary, BMIbaby, also flies to Ireland West Airport Knock.
Mr Walsh says IAG, which was formed following a merger of British Airways and Iberia, will retain BMI's Belfast to Heathrow slots. He said he also wants to retain the Dublin to Heathrow slot.
He said the scale of BMI's Dublin to Heathrow services are small and this may be looked at when the deal is complete.
IAG plans to buy BMI from Lufthansa for £172.5m (around €207m) in cash, however Lufthansa could sell its BMI Regional and BMIbaby units before the deal completes, which would impact on the price.
Mr Walsh, a former chief executive of Aer Lingus, said the main interest of IAG centres on BMI's valuable Heathrow slots.
He said BMI operate small aircraft and he wants bigger planes to be used in Heathrow to make the business more profitable.
He accepted the airline industry faces many challenges but said he believes it is in a better position than after the collapse of Lehman Brothers in 2008.
He said, however, that eurozone leaders need to get their act together to solve the debt crisis and that strong leadership has been sadly lacking up to this point.
On the current code-sharing deal between British Airways and Aer Lingus, Mr Walsh said he hopes to retain this very successful link.
He said the BMI deal is expected to be completed by March and adds that it is a very important development for IAG.
BMI, which employs more than 3,600 staff and flies to Europe, Middle East and Africa and destinations within the UK, made a £153m pre-tax loss in the year to 2010.
