Virgin Atlantic Flight Sale

[chmurf]

TBH - I am surprised there are any child fares at all. They take up the same seat and have the same baggage allowance.
.

most passenger flights also carry freight

A plane can only carry a maximum payload (passengers + luggage + freight)
(see MTOW = Maximum Take Off Weight)

airlines will use weight estimates to calculate the total mass of all passengers on board
Those weight estimates are roughly 80kg for a male pax, and 35kg for a child.

1 child on board instead of an adult, means that a potential 45kg of freight can be added in the hold.
And freight earns the airline a lot of money.

It's a very rough explanation, but basically a child is lighter than an adult.
Some airline give it back to you with child fares, some don't

 

[Lesleyluvsdisney]

I just booked on Thursday. Flights had been sitting at roughly £730pp since June. Got premium economy for £830pp