An unnamed senior European Union official has told the Financial Times that IAG International Airlines Group might fall foul of the bloc's control and ownership rules after Brexit and thus lose market access.

The holding is currently working with the EU regulators to ensure that its airlines retain access to the liberalised EU Open Skies regime after the United Kingdom leaves the bloc on March 29, 2019.

According to EU law, an airline has to be majority owned and controlled by EU nationals to be granted access to the Open Skies.

IAG's strategy has thus far focussed on stressing its constituent carriers British Airways and Iberia are, in fact, British- and Spanish-based airlines, respectively. Local units - British trust LDC and Spanish firm Garanair - own 50.1% of voting shares in the respective airlines, while IAG itself controls a minority of voting shares. However, IAG controls the bulk of economic rights, of which LDC and Garanair have almost none.

IAG has thus far argued that the local ownership of voting rights would ensure EU control and ownership post-Brexit, regardless of the ownership of the economic rights.

The holding company itself is registered in Spain but nonetheless might be considered a non-EU entity after Brexit if the share of non-EU (then including British) shareholders exceeds 50%.

IAG could potentially buy shares from its British shareholders, although this process would likely be lengthy and could have implications for the group airlines' access to the UK market.