Delta Air Lines and Northwest Airlines' merger was approved yesterday by the Justice Department, creating the world's biggest airline. Both emerged from bankruptcy in the spring of 2007.
Bankruptcy which can allow reductions in labor costs, pensions, and the shedding of costly assets, such as planes and redundant routes, often helps potential partners realign their operations. Mergers can yield many of the same benefits but are often viewed as expensive and sloppy, especially if cultures differ. The Delta and Northwest deal was held up for awhile as pilot unions debate seniority integration.
Here is a table of how fleet sizes have changed since airlines have merged. On an annualized basis, most fleets have grown less than 1% per year. Only low cost players Southwest and AirTran have significantly grown their fleets.