No, do not have a specific plane factory.
Have "aircraft production facilities" as one possible target, heavily defended in each country's hinterland behind the uncapturables. Have a sliding ENY/Perk system-the more you bomb aircraft production facilities, the higher the price goes on perk planes. Unperked high ENY planes would pick up a price.
Of course, this would require a few changes. First, the ENY would be updated. It is silly that a fighter like the 109 K-4 or Yak-9U is 20 ENY, while the Ta-152 is 5. Second, I would get rid of people being ENYed out of either perk planes or high ENY planes. Instead, as I alluded to, flying them would simply involve a perk cost. Third, and this is only tangentially related, but interesting, I would give practically every aircraft except the most basic models a light perk price. Of course, I would also give each AH player a stipend of 100 perks a tour so no one would be doomed to never flying an La-7 or a Spit16, no matter how inept at earning perks.
You could do similar things for say, fuel, ammo, or ord. Bomb enough production facilities for those into the ground, and taking off with a full load could cost perks.