Are wet tantalum capacitors still used in really mission critical things, like whatever steps down engine alternator supplied voltage on a f22 to avionics circuit board level voltages?
Wet Tantalum caps have terrible vibration/shock sensitivities. I would use ceramic caps in aerospace 100 times out of 100 rather than consider wet tantalums. At least ceramics are repeatably manufactured and can be mounted J-lead to reduce shock loads. The tants will just randomly break open on you.
Not sure what they're currently used in, but I wouldn't consider them for new applications.