A warm welcome to the CameraLabs forums.
I'm retired now but I used to carry a compact 35mm film camera in the flight bag. I hardly ever packed my OM2 SLR because of the difficulty of keeping it out of harm's way. Maybe your bag has less in the way of the muck and rubbish that mine seemed to collect.
As you know, excess UV is something of an issue at altitude even with the filtering effects of the flight deck windows. Maybe digital sensors are different but the only thing that UV ever did for me was produce an excess of blue in my pictures. IR is a problem for digital sensors as they are too sensitive to it. As a result digital cameras incorporate an IR filter just in front of the sensor. You can
buy various models with this filter replaced by clear glass - check out this Hutech
page for models suitable for IR and UV light. You can always add extra filters to convert the camera back for normal
The issues I used to face were the lack of any foreground objects to give most aerial landscape shots any real sense of depth. Lacking any zoom capability I used to generally avoid air to air shots.
Given your interest in IR and UV as well as normal photography I would opt for a modified Canon 40D (but then as a 40D owner I would say that!) and a few image stabilised lenses (might be an idea to check the lens spectral responses). If I was still flying I'd pack a Canon PowerShot G9 but then I wouldn't be after the wideband capabilities. The smaller lens diameter is also less likely to test the optical qualities of the flight deck windows.