[quote=@Cyclone]
Guided missiles can be outran or outsmarted ( I've heard it said that the early infrared heat-seeking ones could be tricked by aircraft dumping containers full of hot coals) so I'm not so sure that it would be as game breaking as you say.

Overall a decent wing of fighters seems infinitely more dangerous than a few primitive ground to air missiles, especially since it would take a lot to bring down an aircraft ad you said.
[/quote]The fact you actually need to trick them instead of the missiles only being effective in suppressive fire is telling enough.
Sure, for the sake of near-100% success even modern batteries unload dozens of missiles on a single aircraft but it's far better than what they had in WW2.

Guided missiles also mean you have a reliable rocket technology with decent range and that you can miniaturize various technologies which WW2 era militiaries usually could only dream of.
The only known guided AA missile in WW2 was basically as big as the V1 if not larger and required an entire building to control.

Even ignoring these, missiles are a bad idea for your nation because they require decent technology base and industry while shells could be pretty much created by even primitive levels of industrialization. Third World countries nowadays can create thousands of guns and swarms of ammunition with limited tools and purely manual labor.

That and I can't see why you need guided missiles instead of relying on the same kind of AA defenses as what everybody else has.