Italy denied landing rights at its Sigonella air base in Sicily to U.S. military aircraft involved in the war against Iran, Corriere della Sera reported on March 31, citing government sources. Similarly, France blocked Israel from using its airspace to transport U.S. weapons intended for use in the conflict in Iran, Reuters reported the same day, citing diplomatic sources.

Spain took a critical stance on the conflict early on, explicitly condemning the U.S.-Israeli strikes as destabilizing and illegal and barring the use of its Rota and Moron air bases, jointly operated with the United States, for attacks on Iran. European allies' repeated refusals to assist U.S. and Israeli operations have drawn sharp criticism from U.S. President Donald Trump, who in a March 31 Truth Social post urged allies to join efforts to reopen the Strait of Hormuz and specifically criticized France for blocking military flights to Israel.