The merger between Delta Air Lines (DL) and Northwest Airlines, announced this week, has been long in coming. The speculation and talks have lasted months. But it is good news for the aviation industry.It might just be the move to trigger a spate of similar take overs and mergers bringing some much-needed realism to the industry.More intriguingly, it might have considerable consequences for Europe and European carriers.DL and Northwest gave as their rationale for merging the slow down, quite possibly sinking into recession, in the American economy, the rocketing price of jet fuel and the intense competition in the market. The first, if it continues, will sooner or later hit business travel with the number of travellers dropping. This will increase the competition for a smaller number of travellers. The second is the most worrying of all because if it keeps on rising at the present rate, airlines are likely to be forced to consider the the scale of their operations.Teaming up with another airline is a proven way of both achieving substantial costs by synergies and reducing the competition. Both Air France KLM and Lufthansa, when it integrated SWISS into its operation, were surprised about the level of savings achieved. Delta, as the new airline will be called, has estimated its could make $1bn of saving from the merger and there is little reason to doubt it will be a high figure.But the announcement of the merger came just after the US Department of Transportation (DoT) indicated it was likely to approve anti-trust immunity for six carriers in the SkyTeam Alliance. These were Delta Air Lines, Northwest, Air France, KLM, CSA Czech and Alitalia. The DoT did not seem to be just approving the alliance but positively encouraging it.In a statement, the department said the alliance was in the public interest because "it features a proposed new and highly integrated joint venture that will likely produce efficiencies and provide consumers with additional price and service options, such as lower fares and more non-stop and connecting flights." So the DoT is approving an alliance between Delta, the world's new largest carrier, and Air France KLM, the largest carrier in Europe.This is likely to lead, at the very least, to BA and American Airlines, both members of the oneworld alliance, wondering if they applied to the DoT again for anti-trust immunity, it might be granted instead of being turned down as on previous occasions. Star Alliance members Lufthansa and United Airlines might also wonder if they could construct a closer relationship on the strength of the SkyTeam approval.But the relationships between the SkyTeam members goes deeper. AF and DL have a joint venture where they have pooled their transatlantic services. KLM and Northwest have had a similarly close relationship for many years.With AF KLM merged this side of the Atlantic and their respective partners merged on the other side, how long will be be before these four once separate carriers merge or at the very least act together so that each is dependent on the other. It would seem a matter of time.And this might just have consequences for the new round of the EC-US Open Skies talks which begin soon. This is for the second stage of the deal, for a relaxation of the American regulations on foreign ownership of US-based airlines.This is something which US politicians have hotly opposed for reasons ranging from protectionism to national security and fear of job losses. With a recession on the horizon, there are already calls in America, especially among Democrats, for protectionist measures which does not augur well for the success for the talks if Hillary Clinton or Barack Obama reach the White House.But if it is clear that US and European carriers can work closely together and are dependent on each other, some of those objections might melt away.The DL/Northwest merger coupled with the extensive antitrust immunity for the SkyTeam members could just be the example that opens the way for a genuine transatlantic co-operation.