I can speak from the Army side. I want to correct Flash, who talked about how little flight time guys above O-3 get in the Army. The correct assertion is how little flight time guys above O-2 get in the Army. We are promoting two of our O-2s to O-3 next week and their setiment is "my flying career is over."
In the Army, you have to be in a line troop/company to be any type of priority to fly. These folks are designated "FAC 1" and have flying mins of 70 hours every 6 months, but fly about 4 times that in garrison, 8 times that in combat. They are to maintain a "high degree of tactical proficiency." In a line troop, you have around 18 warrants, two O-2s and one O-3 who is the commander. In flight school, each class is split 50/50 warrants and O-1s. You do the math.
Typical career progression: Go to flight school and be really excited about flying. Go to your unit and IF you are lucky, become a platoon leader in a line troop right away (though many people get a platoon in the maintenance company or are stuck at the battalion level planning ops and making powerpoint slides for a while first). Fly your ass off for the 12-15 months you are a platoon leader, make pilot in command, then get whisked off to staff. Staff officer options are personnel (S1), intel (S2), operations (S3), or supply (S4). This is not what you came in the Army for so you are pretty miserable. You get yelled at by the battalion commander every week at command and staff because someone's officer evaluation report is late or because the water bottle coolers he wanted three months ago havent arrived. On your way in and out of meetings you pass the warrants that you used to fly with all the time coming in to grab their goggles and turn in their flight plan and go fly. They tease you on the way. This job lasts for two years. Then you go to the captains career course, no flying for 6 months but you learn the military decision making process and how to make better slides. Then its back to a battalion level or even brigade level staff job for another 1-3 years where you are a staff bitch for some major who is trying really hard to get recommended for command and has already divorced his wife so he's not sure why you want to go home at 8pm when you can work til midnight. Anyway, right before you call it quits (since your service obligation for flight school is almost up), you get to command a line troop (well, 50% of you do, the rest get to command non-flying companies and become out of sight, out of mind. You forget what a helicopter looks like). Commanding is really cool, you own 10 aircraft, you are pretty rusty at the flying thing since you havent done it in 3 years but as long as you arent an arrogant prick the warrants will forgive you and get your back because you can make their life a living hell (and a lot of O-3s with chips on their shoulder do just that). Anyway, then you become proficient again, you get your pilot in command orders back which were rescinded when you were flying a D-E-S-K. You are pretty happy. After 12-15 months, you are out of command. And guess what? Its back to staff...S1..S2...S3...S4.... You decide what the hell, I'll go for a battalion command even though that is about 6 years off. You now have about 1200 hours in the aircraft after 6 years of flying so its not like you can get a job when you get out anyway. So, you get really bitter and angry and start treating the junior captains around you like crap. Especially if you are in an area, like an Iraq deployment, where they get to fly a lot and you didnt. You tell them they can only fly once a week and on your way out of the door you yell at them because their powerpoint slides suck. You hide the fact that you couldnt shoot an instrument approach if your life depended on it. When you do fly, the line troops make you fly with an instructor or another senior warrant so you dont kill yourself.
So, in a standard 10 year career, you have spent 2-2.5 years in FAC1 flying positions. You have 1000 hours. 1500 only if you happened to be deployed during both your platoon leader time and troop command time.
Now for the warrant track. You go to flight school. You get to your first unit and are sent immediately to a line troop. You are told to make sure the fridge is stocked with drinks and study your ass off because you start flying tomorrow. You are the priority to fly. You fly your ass off, make pilot in command around the same time your platoon leader does. He goes to meetings and gets yelled at a lot, you stock the fridge, fly, and chill out on your days off. After two years and one deployment where you logged 1000 hours in a year, you decide you want to be an instructor so you to the IPC and come back to your unit. You are now training everyone else, and flying with the staff officers. After 4-5 years you PCS to another unit where you are put directly into a line troop. You consider getting out at 10 years because with your 3000 hours you are pretty marketable but you decide to stay in. In fact, you stay in a line troop until you have about 19 years of service, then and maybe then you get moved to battalion level job, but that is just because you are the senior instructor pilot. You become yoda. People climb mountains to get your advice. You work around a lot of bitter O-3s but you dont really see them a lot because you are still flying as much as you did in the line troop. You have to fly with the battalion commander a lot to keep him from killing himself. After 20 years you have around 5000 hours and can fly with your pinky finger. You laugh when you battalion commander gets his masters wings and treats it like a medal of honor.
So there is the difference. Anyone still wonder why commissioned officers redesignate to warrant and take a pay cut? It gets old to get called staff puke every time you walk in to get your flight gear when the only thing you ever wanted to be was a pilot and you fell for it, hook line and sinker, when the army said you would be.