I have Starboard Hypernut and it doesn't have air valve.
Is it safe (will not occur delamination) to transport SUP without air valve by plane? Why most of SB sup's do not have air valves?

It's nothing to worry about and becoming common now because most people just tighten and forget without any problems.. and airline cargo holds are now pressurized and temperature controlled unlike the old days.. Even though it's safe I wouldn't be leaving it in the sun or in your car on a very hot day..