While they monitors don't have to be the exact same model, they should be very close in size, shape, bezel size, etc, if you're going to attempt to run triple screen IMO. I did it for a short time, 3 24" 144hz Asus 1080p monitors, back when they were the first 144hz gaming monitors around, about 6 years ago now. It was great for the time, but IMO either VR or going to a larger high end gaming LCD is a better option now. Still, setting up 3 of the new 60" gaming LCDs coming this year would be very cool. When I was a kid I dreamed of a basement airline cockpit with screens that big, and now you could easily do it with these 60" large Gsync/etc/etc gaming LCDs coming.
Just do a google search of triple screen or nvidia surround, whatever, you'll get lots of pics and options. Honestly though, considering the $ investment to get 3 screens that are similar/same, and the GPU to run them...I'd go VR if you haven't already. You being a pilot would truly appreciate VR, and the Rift is 1/2 the cost it was when I bought all of my VR gear.