These types of debates are going for few decades already.
1,3trln is joint air-force budget for next 80 years (since F-35 is intended to cover 90% of all air-force&#x2F;navy&#x2F;marines air tasks), includes not only 2500 highly sophisticated vehicles them-self, but maintenance, and probably training and weapons, and covers 50% of national security problems in modern world.
I think 1.3trln is moderate price for that.