British Airways have said without its takeover of bmi, all 2,700 jobs at the company could have been lost.
The jobs facing the axe are at bmi's head office at Castle Donington in Leicestershire and at regional airports.
Jobs secured include 1,100 cabin crew, pilots and engineers at Heathrow and up to 400 passenger service roles at Heathrow's Terminal One.
The takeover of bmi by British Airways is set to lead to up to 1,200 job losses, the airline announced.
Northern Ireland will benefit from linking in to the British Airways network, according to Secretary of State Owen Paterson.
British Airways' parent company International Consolidated Airlines Group (IAG) has confirmed the airline's Belfast-Heathrow route is secure following their acquisition of bmi.
He said: "Heathrow gives opportunities for global connections to and from Northern Ireland that are not available at the other London airports. Those connections are absolutely vital to our investment and trade.
"The European Commission decision today, opening the way for the sale to proceed, is good news for the Northern Ireland economy.
"Part of building up the economy here is making Northern Ireland readily accessible to the world and linking in to the whole BA network will be a huge advantage."
Low-fare Irish carrier Ryanair say the only significant EU airline merger that had been prohibited was its own merger with Irish airline Aer Lingus.
Ryanair boss Michael O'Leary has criticised the International Consolidated Airlines Group's acquisition of bmi.
He said: "Today's rubber-stamping of BA's purchase of bmi shows yet again that the European Commission has one rule for Europe's flag-carriers, but different rules for Ryanair.
"While we have no objection to BA's acquisition of bmi, it will undoubtedly lead to higher fares and higher fuel surcharges, and give BA/IAG even greater control (over 55% of slots) at the heavily congested Heathrow."
Jim McAuslan, general secretary of pilots' union Balpa says the International Consolidated Airlines Group's acquisition of bmi could put jobs at risk.
He said: "IAG has so far made it clear that they only intend to run the bmi mainline operation and that although they must take over the bmibaby and bmi regional businesses as part of the transaction, these businesses do not figure in their plans.
"Balpa will be looking to protect those jobs whether in IAG or with any other potential buyer. But even with the Heathrow-based bmi mainline there is a huge amount of work to do to integrate and create a sustainable operation, and we recognise this is not going to be a painless process."
Willie Walsh, Chief Executive of the International Consolidated Airlines Group (IAG) says the acquisition of UK airline bmi can benefit British business. He said:
As part of the regulatory process, British Airways' parent company International Consolidated Airlines Group (IAG) has offered the following commitments to the European Commission.
- Seven daily take-off and landing slot pairs to be used between Heathrow and either Edinburgh and/or Aberdeen.
- Five daily slot pairs to be used between Heathrow and the following destinations: Nice, Cairo, Riyadh, Moscow, Edinburgh and/or Aberdeen.
- Two Heathrow daily slot pairs will be leased to airline Transaero for use on flights to Moscow.
- Other airlines can apply for seats on the integrated BA/bmi short and mid-haul network for their transfer passengers.
The controversial takeover of UK airline bmi by British Airways' parent company has been approved by the European Commission.
International Consolidated Airlines Group (IAG) have completed the deal, but in return for Brussels' agreement, BA's owners must give up 14 pairs of daily take-off and landing slots at London Heathrow to boost competition in the sector.