>> I would like to start listening to the millitary bands, but believe I"ll need a different scanner in addition to my pro96.
If you are referring to the "lack" of frequency coverage in the 225-400 MHz range with the Pro 96, you can enable that range with the Win 96 software. From the comments I've seen in the past, though, the sensitivity of the Pro 96 in that frequency range seems to vary from "deaf" to "decent."
>> What do you guys use to monitor aircraft?
I don't do much aircraft listening, but have a R.S. Pro 2035, with Opto board installed, for that purpose. The board provides for computer control, as well as for programming scan / search lists.
The Pro 2035, 2042, 2004, 2005 and 2006 scanners are all good civilian and military air receivers, with the ability to set the proper modulation mode for the channel. All of these scanners were well-made by GRE, with the exception of some problems with the LED displays not lighting on the last three models above.
Although all the above scanners are still in demand for their conventional channel sensitivity, you may find some good prices for used units online ... all of these scanners were made before any trunking scanners were available.
If you want a second scanner that can also do trunking and digital, I have read some good comments regarding the Uniden 296D handheld / 796D base-mobile scanners.