Nothing new in the charter airlines hiring in extra capacity during the peak season - its been happening for years as has UK charter airlines offloading capacity in the UK off peak season to other places - e.g the Sunwing leases by various UK airlines. No charter airline can equip for the hoped for peak and then find they have expensive slack should bookings be down. Instead they hire in from the likes of Titan in the UK or other airlines that specialise in short term leases such as Mint.