I've tried making Tanks able to attack air in every conceivable way i thought possible in DatEdit. by checking off that the weapon that the turret uses could attack air, by making the turret have the goliath hellfire missile pack as an air weapon, setting the hellfire missile pack to the ground weapon but checking off both ground and air for the hellfire missile weapon...

well they all crash the game. There must be a way to get tanks to hit air, right?

Iscript.

With IceCC or PyICE, find the entry for the siege tank turret. Open it up, and add entries for the AirAttkInit. Then save it as a txt file and compile it. Then add the resulting iscript.bin file to your mpq/exe under scripts\.

Not just AirAttkInit, but also AirAttkRpt and AirAttkToIdle.

Also: http://www.staredit.net/wiki/Creating_an_attack_via_Iscript.bin
And: http://www.staredit.net/wiki.php

Help yourself! There's a lot of reading material there. If you can't get a satisfactory answer from there or are confused with the material there, feel free to ask.

in summary

1-unit.dat

2-iscript

3-get ready to roll

On a related note, giving a unit a new type of ability usually requires you to update its iscript.

thanks! I had no idea you could edit scripts like that.