Going back over 20 years in his research, he found that on average, Air Force types retire at one-half a paygrade less than Army. Further, while it takes longer to make rank in the lower grades of the Air Force (as opposed to the Army), it seems to be easier to make senior rank (E-7, -8, and -9) in the Air Force than in the Army. So if one embarks on a career in the Air Force and you do more than 15 years, you can retire with the same (or perhaps a bit more) rank than you would in the Army.

If you do less than 15 years, you would probably leave with more rank in the Army.