President Donald Trump had said Iran couldn't "do a thing" about American aircraft operating over its territory, insisting its air defences had been significantly weakened.
His Defence Secretary Pete Hegseth also said the US had achieved "air superiority" over Iran.
So, Friday's downing of a F-15 Eagle is a significant blow to Washington DC.
It suggests Iran is still able to defend its skies, even if at a limited capacity.
The stakes could rise further, though, depending on who the missing weapons systems officer is captured, or rescued, by.
