Recently I had an opportunity to test some of the internet's advice for taking pens on airplanes. I ended up putting together several tips & tricks into a routine that worked quite well. It's nothing fancy but it does the job!
All the pens were placed in a zippered plastic bag, so their tips were pointed in the same direction. The water brush was emptied to avoid any potential issues with airport security.
As soon as we were seated, I pulled out the bag of pens and slipped it into the seat pouch (tips up, of course). This way not only were they safe and totally secured into an upright position, but I could unzip the bag and use the pens while flying with very little fuss.
I used several of the pens during the flight - including a Pilot Penmanship fountain pen with a half-full cartridge. None of the pens shed a drop of ink or had any other troubles, during or after the flight.
Surely a bit of bad luck could have caused this to go differently but I feel confident that this routine will minimize the chances of a spill, and mitigate the damage should the worst occur.