I am actually quite surprised by this and to me it looks like people are just overcomplicating things. You get on a plane, you turn on Airplane Mode. Simple. It would never ever occur to me in a million years to turn on Airplane Mode on my phone, but then go ahead and just turn off the wifi on my iPad. Also, isn't Bluetooth also supposed to be off, which Airplane Mode would take care of?

EDIT: This is what Airplane Mode looks like https://i.imgur.com/mEMYdL6.jpg https://i.imgur.com/4L3uZmm.jpg