It escapes me, why a civilian airline was in air in first place. Shouldn’t ATC be asked to stop flight movements for the duration of missile launches?

In tense war (like) situations, things go wrong. To me, letting civilian airline in air, itself was serious wrong.

What a terrible collateral.

I can think of several reasons:

- despite its belligerent actions in Iraq, Iran wanted to live up to Khamenei's tweet to Trump "1st. You can't do anything". [0]

- if Iranian leadership was actually fearing American reprisals after their missile strikes at Iraqi bases, they may have wanted to maintain civilian air traffic as human shields, because if only military planes were allowed to fly and an actual war broke out, American total air superiority would benefit them. Having civilian planes flying would make it easier for Iranian military operations to mingle in.

[0] https://twitter.com/khamenei_ir/status/1212301034871279616