You should be able to upgrade spring traps to 2x2 where pekka and golems can now be launched.
It would begin
level 2 as a 2x1 just a bigger spring trap 3 mil
Level 3 2x2 6 mil
Also add a poison trap. Ground troops only.
An air snare trap. Giant net comes out in a 3x3 area gobbling up any air troops for 3 seconds. During this time they are on the ground. Alowing canons and mortars to also hit them.