So I have this Citizen AT2215-07E Eco-Drive Tachymeter. I was trying out square watches and this one caught my eye on Ebay as NOS for a reasonable price. I already had a Brycen style Citizen Tachymeter that I really liked the fit and finish of and the sweep arm was very smooth so I was expecting more of the same. When the new watch arrived, it had a few niggles. It took me a bit to get it back to full charge and the sweep arm moves in second pulses. The one issue I really had with the watch was how cheap and nasty the band was. Some sort of bias ply Naugahyde creation. I pitched it right away. Then came my search for a replacement band and to my mind a NATO was the way to go. The only problem is that Citizen for some reason sizes these at 26mm and I was having a real issue finding anything in that size range. Eventually, I just gave up and went with a Black and Red striped number from Crown and Buckle. The 1mm Gap on either side is only slightly annoying and I think I'll just keep this one as a beater watch for the time being.
I also decided to fit my Fleiger B Dial with another Crown and Buckle striped number in 20mm. I can see myself swapping back and forth between the NATO and the leather on this one but I will admit, I do like it a lot.
If I had the square Eco-Drive, I would want to find a strap that actually fit, I couldn't live with a gap like that (not sure even James Bond could either, if he actually paid attention to what he was wearing). As for your Flieger, I don't think the Nato works, I would go with vintage leather myself.
With your Citizen AT2215-07E Eco-Drive Tachymeter, the colour scheme looks great. However, I would keep looking for a NATO strap that fits the lugs width properly for I would find the gap to be too much of a distraction. With your type 2 Pilot watch, the NATO strap, with its multi strips, looks great on the watch.