British Airways has revealed that its Airbus A380s will have a four-class layout with 469 seats, comprising 212 on the upper deck and 257 on the lower.
It has also disclosed that its Boeing 787-8s will be fitted with 214 seats in three classes.
But the carrier has yet to identify the routes on which the jets will be deployed. The initial destinations will be unveiled in spring 2013.
The A380s will have 14 first-class seats and 44 business-class seats on the main deck, plus 199 seats in the economy cabin.
It will feature a premium-economy section, but no first-class cabin, on the upper deck which will be configured with 53 business-class, 55 premium-economy and 104 economy seats.
Four 787s will be delivered to the carrier next year, the first arriving in May. BA will introduce its first A380 in July, with two more delivered in August and October.
It will also take two more Boeing 777-300ERs during September-October 2013.
BA will equip its new aircraft with a Thales in-flight entertainment system, while in-seat power will be available in all cabins.
Twelve A380s are on order for the airline as well as 24 787s, of which eight will be -8s. BA has yet to disclose the planned layout of the 16 larger 787-9s. "They could have three- or four-cabin configurations," it says.