Lots of drift here...but good dialogue.
To the OP: philosophical responses...what do you want to "do" with your life? Work is either a means to an end or, for some, an end in its self. If a means to an end (pay and retirement) I am an advocate of risk reduction and diversification. If going to the airline is what you want to wake up and go "do" as that means or an end, then I would go now. If you still find value and want to wake up and put on the military uniform, do that. There is money behind both your options... what do you want to do with your life? If your purpose (hope not) is based solely on a secure retirement I'd punch and start diversifying that retirement with an airline 401k. But if you still feel called to serve then do that. Again at 43 what are your priorities? No judgement I simply don't see/know all your other priorities other than financial. And I am certain you have them. Best of luck with your transition.
Tougher call for the man with 16+yrs.
I know 10+ guys who punched for airlines in their teens prior to 9/11...with no real back up plan. Scrambled for ANG/Reserve jobs. Yours is truly a risky decision. The probably of a completely lost 20-yr Military pension versus being furloughed with the hope of guard/reserve bumming (plan B) as supplemental income seems to favor getting the military AD retirement... again pure financial decision and I am sure there are other factors too. Man-days and dollars have been cut back significantly. They are still out there but is very unit-to-unit dependent. I'd develop and research the viability of your plan B thoroughly before leaving 16 years on the table.
Best of luck to you both...Happy New Year to all!