Hi!!!!
Look i have an idea....what about Stealth Air transport?
it should be given when you use MoS strategy and it should be an upgrade too...like stealths (airplanes) i mean when you don't the upgrade you don't have them when you use MoS you have them
and when you open the upgrade you have it every strategy you use
Stealth air transport ;
*Stealth*
Attack : 1
Defense : 2
Critical : 4
HP:6
Range : 14
View : 25
Capacity : 4
cost : 700
*stealth ; air transport can carry only marines*
that's why it has also 4 capacity and it costs more..(llower hp and critical too)