Which US Army airframes (and units) fly the most?

Pick a mission not an airframe. The AH are maintenance heavy but I’ve never missed a flight due to it.

I will echo what CW3 (Join to see) said: go with the mission-set that you'd get the most satisfaction out of. I flew 64s for a few years, and it's still my favorite to fly; however, to your second part of the question, "which units fly the most," fly whatever you can to get some solid NVG hours out of flight school, and then assess for the 160th SOAR when the time is right. Regardless of whether we're at war (which is where I got the vast majority of my flight time), the 160th is always training and flying. Have fun in flight school - it was easily my favorite year and a half in the Army!!

Depends on what roll you want to perform? Also keep in mind based on your class rank you choose in order. They will have so many available selections of each aircraft per class. As an Apache driver I flew about 800 hours in one combat tour. That is not the avg by any means as it is much less at your home station. Blackhawks tends to fly more because it’s mission is varied. Plus you can fly lift or Medical. Chinooks fly, maybe not as much as hawks, but your get your time. Apaches have to train tactics, but it varies as well. Do you want to do security, blow stuff up? Apaches. Do you want to move troops into battle, ferry people, pick up wounded soldiers? Blackhawks. Or do you want to move equipment, take airborne soldiers to jump, ferry larger groups of soldiers around? Chinooks. I think the UH-72 Lakota is an option now as well, especially since the OH-58 Kiowa went to the bone yard.