Passengers who fly with Ryanair could soon be able to clock up frequent flyer air miles that they will be able to use to jet off around the world - with rival airline British Airways.
It's a quirk of a concession that IAG has offered the European Commission to enable its €1.36bn (£1bn) takeover of Aer Lingus to go ahead.
Ryanair boss Michael O'Leary has said the airline intended to bid for five take-off and landing slots at London's Gatwick airport that must be relinquished by BA owner IAG before the Aer Lingus acquisition is allowed to proceed.
The European Commission has published details of how the slot reallocation would work if implemented.
It has insisted that any airline that secures control of any of the five slots that are being surrendered by IAG at Gatwick must be allowed access to IAG's frequent flyer programme Avios.
That is if the new entrant does not already have a frequent flyer programme of its own in place.
However, the points on IAG's frequent flyer programme would only be clocked up by a rival airlines' passengers on services using one of the five slots that will be relinquished at London's Gatwick airport.