Delta's rumoured interest in making a run for Oneworld airline group AMR could turn the joint ventures forged in the past few years among the big three alliance partners upside down.

The SkyTeam carrier's reported analysis of possibly taking over American Airlines parent AMR - currently in Chapter 11 bankruptcy protection - led to speculation over how such a move would affect the powerhouse joint ventures those groups created to essentially operate as single global entity, without violating various foreign ownership laws.

But the promised value of those alliances appears elusive. United-Continental has had to make payouts for outperformance in its joint venture with Star partners Lufthansa and Air Canada, while American has stated that it perhaps anticipated getting traction from joint sales with its Oneworld transatlantic joint venture partners a bit too soon.

For the second quarter of 2011, yields on American's transatlantic markets dropped by 2.3% year on year, having grown by approximately 22% in the same timeframe in 2010 - prior to the launch of the joint venture. Revenue per available seat mile (RASM) on American's transatlantic routes in the second quarter of 2011 fell by 4.7%, having increased by more than a quarter during the same period of 2010.

"Antitrust immunity between American and British Airways was supposed to save the RASM day for AMR, until it didn't," analysts at financial firm JP Morgan say in a report examining a potential American-Delta deal. "While the industry has spent years forming complex and reportedly lucrative joint ventures, the financial dividends are dubious, in our view," the report added.

Still, potential alliance jostling triggered by tie-ups between Delta and American, or even US Airways and American, is "the single most murky and complex area of a potential merger", the analysts concluded. They find it hard to believe European regulators would offer their blessing on a deal significantly undermining Oneworld or SkyTeam, where Delta would potentially migrate to Oneworld.

Just two years ago, Oneworld's US anchor American teamed up with private equity firm TPG and fellow alliance partners to offer $1.4 billion to Japan Airlines. This was an effort to bring the carrier back from the brink and ensure it remained in the Oneworld fold, rather than jumping ship to Delta and SkyTeam, who rallied to offer roughly $1 billion to woo beleaguered JAL.

Now fellow Oneworld founder British Airways and its sister carrier Iberia face a strikingly similar battle to ward off Delta deepening its advances toward American.

MIT research engineer William Swelbar concludes any hint of interest by Delta "smacks of a direct frontal assault" on Oneworld. "I fully expect that British Airways and other Oneworld partners will stand by American if their access to the traffic rich US market is potentially compromised by a competing bid," he says.

Source: Air Transport Intelligence news