IAG, which owns British Airways, Aer Lingus, Iberia and budget brands Level and Vueling, surprised the industry by acquiring a 4.61% stake in Norwegian last week, saying it “intended to establish a position… to initiate discussions with Norwegian, including the possibility of a full offer”, writes Gary Noakes.

Norwegian founder and chief executive Bjorn Kos owns 27% of the firm – the largest slice. He has said he does not wish to sell, but other shares are spread among institutional investors, making a bid possible.

IAG may reveal more when it details first quarter results on May 4, four days before Norwegian’s annual general meeting.

Figures confirm easyJet as Gatwick’s biggest airline, with 14.2 million seats this summer, whereas BA offers 6.5 million. A takeover of Norwegian would see IAG gain nearly 4.4 million seats. Adding this to Aer Lingus, Iberia Express and Vueling’s Gatwick capacity would give IAG 12.45 million seats at the airport this summer.

IAG has already grown at Gatwick after buying former Monarch Airlines slots. This summer, BA has added 1.3 million Gatwick seats and any full bid for Norwegian would have to satisfy regulators.

However, aviation consultant John Strickland said: “IAG will have weighed competition implications of any further moves, particularly in the UK-transatlantic market.”

Norwegian would be a good fit for IAG, which launched low-cost long-haul airline Level at Barcelona, a Norwegian base. Barcelona is also home to IAG’s Vueling, a short-haul budget airline. IAG would also gain a significant brand in Scandinavia, where Norwegian has grown.

Norwegian said it had not been in any discussions or dialogue with IAG about the matter.