TL;DR - expect a lot more being siphoned from your gross pay before you get your net pay unlike the military. For me personally, net pay + Roth TSP contribution is about 62% of my gross pay. That obviously will vary by individual situation, but it's certain that more will come out of your FAA paycheck than military. Probably much more. FAA is still a pretty awesome place to work though. Actually combination of FAA/USAF is a good one. Go Guard/Reserves 🙂
Some costs and other things for you all to factor in if you haven't (seems like many here have a good handle on much of it though):
base pay = basic pay + locality. Basically the salary which will be shown on your FOL or LES once you start getting that.
pay period in the FAA is every two weeks
Employee Contribution to FERS annuity: 4.9% of base pay
Taxes - Sometimes military pay is exempt. City I was in has a 3% tax on all my FAA pay but exempted all military pay. State taxes were exempted for any duty done outside the state, which is most common. It's relatively easy to avoid or limit state/local taxes in the military; not so much in the civilian sector. All your pay that doesn't come out as a pre-tax deduction will be hit by federal taxes. That's a sticker shock for some not expecting that, although most people do seem to be aware of that big expense when transitioning out of the military.
Union Dues: 1.4% of base pay. Joining is optional but I'd recommend it. The union isn't perfect but they do a lot more good than bad.
Healthcare: This will vary greatly depending on a number of factors, but mostly if you are single or have a family and how healthy you or your family is.
Medicare and Social Security Taxes are more noticeable since more of your pay is subject to them, just like taxes.
Disability Insurance: A group policy like Unum will run about $20-$40 a pay check. Group policies are inherently weak though to make them affordable. That's not a direct slam on NATCA for recommending UNUM, it's just the nature of group policies. Better than nothing but there are more holes in that type of policy than in Swiss cheese. A good individual policy will run you about 5-6% of the amount you want insured annually assuming you are healthy with no pre-existing conditions. Since a federal disability retirement covers 40% of your high three after the first year (60% the first year), you would want an individual policy that covers 60% of your salary if you want the same salary on disability.
Smaller pay raises for now: For 2020 the White House's request is 0% for federal employees. That only leaves the union negotiated pay raise of 1.6%. The proposal for the military pay raise is 3.1%. Average BAH increase for Air Force is proposed at 3.4% (Army 3.2% and Navy/Marines 3.9%), and BAS increase is proposed at 2.4%. Those are only proposals, and things like BAH are an average (some might see less, some might see much more). There's also longevity raises for military every other year until you hit the top of your rank's pay. Military pay raises of late have felt more palpable than FAA, with the exception of jumps like moving up the D scale or transferring to a higher level facility.
On the plus side though, the FAA has several differential pays and more than likely if you want overtime you will get some throughout the year. Your annual pay is all but certain the be higher than what your base pay actually is, and total compensation for the FAA even at low level facilities is still pretty good. A lot of the compensation goes towards the pension, which is obviously very valuable and getting increasingly difficult to find outside of the public sector. Being able to keep healthcare into retirement when you have to retire before being eligible for Medicare is also huge. Government also matches TSP unlike military unless you opted into BRS or came in after it was made mandatory.
