You don't have to purchase a seat for the baby, however you will have to pay 10% of the applicable fare if you wish to take them onboard as a lap child or use one of the onboard bassinets. If you use the bassinet you will have to hold the baby during take-off, landing and any turbulence during the flight.

If you wish to purchase a seat for the baby (eg to use your own infant carrier) then you will have to pay 75% of the applicable fare.

You cannot put the baby on the floor in an infant carrier.

I hope that helps! Happy travels