In aviation, EU single market rules empowered Ryanair over three decades to defeat all pilot unions across Europe, regardless of the notionally strong power resources on which they were relying in their countries. Nonetheless, in December 2017, a transnational group of union-related pilots, the European Employee Representative Committee was critical in forcing Ryanair to finally recognize trade unions. This study shows that multinationals’ ability to circumvent national union power resources does not necessarily undermine transnational collective action. Hence, transnational union strength does not primarily depend on an aggregation of national power resources, but on union activists’ ability to exploit union-friendly peculiarities that the EU governance regime is also providing. We show that the apparently weaker institutional power resources at EU level provides more effective leverage for transnational collective action than apparently stronger power resources embedded within French, Danish, or Norwegian labour law. This requires an understanding of scale.