I am always very skeptical of the "you must leave 20+ hours between your last dive and your flight" crowd. The vast majority of your off gassing is done in the first four hours after the dive. I have a really hard time believing that after (say) 8 hours subsequent to a dive made within NDLs there is enough residual nitrogen in your system to cause damange simply by a small drop in ambient pressure (most cabins are pressurised to 8,000 feet, which is a pretty darned small drop in ambient pressure).
My old US Navy tables (I know, I know) warn not to fly within 4 hours of diving, or 12 hours if you have been engaging in decompression diving.
My old US Navy tables (I know, I know) warn not to fly within 4 hours of diving, or 12 hours if you have been engaging in decompression diving.