​IAG chief Willie Walsh believes airline alliances are still relevant, owing to restrictions in the air transport industry, but that true corporate mergers are a much more preferable course.

IAG chief Willie Walsh believes airline alliances are still relevant, owing to restrictions in the air transport industry, but that true corporate mergers are a much more preferable course.

The company's primary carriers – British Airways and Iberia – are allied to Oneworld and its latest acquisition, Air Europa, will be rescinding its SkyTeam membership.

But Walsh insists alliances are a "poor substitute" for genuine merger and acquisition activity.

"They're all about revenue synergies," he told an 8 November investor briefing. "Anyone who tells you that there's a cost benefit, or any cost synergy, they're misleading you."

Walsh says alliances have a "role to play" but their structure is proving "fragile" with several carriers, including Air Europa, having shifted allegiance.

IAG's acquisition of Air Europa is, in turn, a response to the defection of LATAM from Oneworld following Delta Air Lines' taking a 20% share in the Latin American operator.

But Walsh has "absolutely no doubt" that the corporate environment that supports alliances will change.

He says he gives "credit" to Delta's investment in LATAM but adds that IAG is not enthusiastic about minority shareholdings – to which carriers are often limited.

"If we see that we can generate strategic value by taking any minority stake in another airline then we would have to consider it," says Walsh.

"But taking a minority stake without having some form of control, or some influence over what the airline is going to do, has no value whatsoever.

"The idea that I would pay a premium to invest on your behalf, and get nothing in relation to control back for that premium, just doesn't make sense."

Delta has a 49% share of Virgin Atlantic and describes the stake as "non-controlling", although Walsh believes it amounts to a minority stake "on paper only". The US carrier also has a 51% holding in Aeromexico, although corporate laws restrict its voting interest to 49%.

Walsh says Delta has done "pretty well" with Aeromexico and adds that its investment in LATAM will prove a "sensible way forward" if it can exert influence over the operator with its 20% interest. LATAM is 10%-owned by Qatar Airways and another near-28% is held by Cueto Group.

"We only see [minority stakes] making sense where you get an element of control," says Walsh.

"If you can't get control or influence then you're like Etihad [Airways]. You think you have control, they take your money, they spend it, and then they tell you to get lost."