SleepCalm drops for kids

So I will be traveling with my 3 under 3 kids it will be a 4 hour flight during the night. I’m afraid they cry in the airplane so I didn’t want to use melatonin like some people recommended and or Benadryl I saw this drops sleep calm kids they are melatonin free. I tried one in my son and he fell asleep in 5 minutes usually it takes him good 20-30 minutes. Do you guys recommend if you have used them?