MOL is quite right. The vast majority of toilet visits on aircraft are totally unnecessary. Disturbing the two people outside you when you are in a window seat, traipsing up and down the aisle disrupting the passenger service, just to adjust hair or fix lipstick. The potential savings are considerable, for instance, Aircraft weight would be significantly reduced since less water would need to be carried for flushing and hand washing, less ventilation air would reduce bleed air requirement and less use of the lavatory lights would all reduce fuel burn. I understand that what is about to be proposed is £1 for no.1, £2 for no.2 and £5 for nothing at all. PTD is to be used to differentiate.