This is an old thread. I have flown a number of commercial aircraft including the 747, 727, and many turbo prop aircraft. I'm presently captain on a 737. I've had a number of good lights, but for the last four or so years I have carried the pelican 7600. Works great and I would recommend to any pilot. The 7600 exceeds any D cell equivalent test.
I've been flying for a number of years with the following setup and never had a problem. First, the 2"D" cell light, our company puts 2 in each aircraft, technically not required for airlines as stated, but I've had ramp checks where the inspector insisted on this. The company provided lights solve this nicely, never use them personally. I carry an 18650 zoomie in a holster on my belt. Never had a problem at security. I use flood for the big picture and can zoom in for details such as the tail and vary the zoom according to need. A quality 18650 battery lasts for several flights or several legs in one night. I have a similar backup light in my backpack just in case. For use in the cockpit, I have a keychain light on my I.D. lanyard. Easier to use and a decent one has more than enough light output for such use, you can get them with a red light if you're worried about night vision.
Really late to this thread, but I just joined up, so I'll toss my hat into the ring on the subject, having been a General Aviation pilot, and a flashlight fiend.
I bought a Surefire Fury Intellitouch a while back, because I wanted the high output that was available; I wasn't thrilled at the idea of the intellitouch feature, but got a good deal so I went with it.
The broad flood beam turned out to be nowhere near what I wanted for outdoors at night, but to my great surprise, the intellitouch makes it an ideal around-the-house light. It cranks the power way down if you're near a reflective surface, so you don't get blinded; it surprised me to see how useful this feature is. If you neew full power, you can override the intellitouch feature by a second click, and you've got a really powerful flood beam.
It seems to me that this would be really useful in both a confined cockpit as well as doing a preflight outside the aircraft. If I were still flying, it would come along with me, for sure.
GA pilot here. I fly with a Lumintop EDC18 and/or Sofirn SC31Pro depending on what I'm doing. The key features for me are: 1) Illuminated power button, 1A) software lock-outs which keep the button illuminated/flashing but won't let it turn on in my bag. 2) Built in battery meter, 3) built-in USB-C charger on the SC31Pro, 4) Both have extremely dim moon modes, 5) Both have extremely powerful high modes for their size. I'd call runtimes very good on both of them.
If it's anywhere near dark, I keep one clipped on the panel or cupholder with the illuminated button facing me. I also use the EDC18 with the diffuser condom as a cockpit light, especially after a flight. Most aircraft cockpits have terribly dim lighting, but the EDC18 has a magnetic base and sticks wonderfully to the overhead panel. Great for making sure I've gotten all of my own items out of the aircraft at the end of the night.