Hello showboat1,
There are two versions of this campaigns pack, both of them included in the ultimate edition: for mods and without mods.
If you want to fly the Curtiss H-75 against the Wildcat, you need the modded version, and for that purpose you need a modded game. You do not need a mods pack though: a mod activator with the latest Buttons (as supplied by SAS), plus all the required individual mods listed in the dedicated read-me will do the job; you must read the read-me dedicated to the mods, and you must apply strictly all instructions.
In the modded version, missions involving the Hawk-75 and the Wildcat also involve the Swordfish and other new slot planes, so please make the effort to install all required plane mods. They involve modded maps as well, so please apply the instructions required for them to work.
SPECIAL VARIANT FOR FLYING THE Hawk-75A-3, AND MS 406 WITHOUT NEW SLOT PLANES INSTALLED: if you have a modded game just with the mods activator from SAS, you may try the unmodded version of my campaigns: in that case you may have the opportunity to fly the Hawk-75A-3 against the Wildcats without any mods installed, but at least the game itself must be modded with the mods activator. Please let me know how it works.
When you install the ultimate edition, use JSGME to enable the modded version OR the unmodded version of the campaigns.
Happy flying,
Vincent