It has been said that you are a soldier first, an officer second, an aviator third. As an army aviator you still have to do ground stuff and you'll have a staff role, whether warrant or commissioned, that will eventually limit your time spent flying. If you make a lot of time to go fly and do some missions like hurricane response, expect 200 hours a year tops as a part timer. Despite what people might tell you, you will not get an active guard reserve job until you have proven yourself to your unit and been accepted into the good old boy system. You will not get an ARNG fixed wing slot. You will spend months working on a flight school packet while a recruiter jerks you around, then you'll go to school for 12-18 months, get back with something like 150 hours, spend two weeks on orders, then go to flying 100-200 hours a year. You might go to a unit with a non-deployable aircraft or you might go to a unit that deploys every 3-4 years. You won't have the time or mental capacity to learn airplanes while you're in flight school. So you can expect your airline goal to still be several years away.
That was deliberately negative as is the tone of this post in general. Try to talk yourself out of it like I am here. I like the army and I like flying. We do some cool stuff. I love the people I fly with. I read the international news, bad people do bad things, and I still feel the same desire to help stop it.
If you want to be an airline pilot, do that. If you want to serve your country by flying america's sons and daughters into combat, do that. You can do both, but they're separate questions.