Unlike ground and naval units, air units have a simple progression with strength and cost increasing together. Cost levels and strength increases: * 14, initial strength 12: Flight - allowing, for example, a fighter with 48/12/8.5 costing 70, or for the same construction cost a reconnaissance-and-blocking craft 0/12/8.5 with four reserve fuel tanks and therefore total range of 42.5 MP between refuelling stops; however, at no additional cost you can research Rocketry to increase the range * 17 +6: Tactics (requiring University and Warrior Code) - also adds to ground unit strength and enables Military Academy and therefore often researched before Flight, regrettably making your earliest air units more costly; however, if you avoid Electronics and Miniaturization and Composites before r