European tour operator TUI Travel has placed a follow-on order for a pair of Boeing 787-8s to take the group's commitments for the Dreamliner to 15.
The group expects to take delivery of the two new aircraft in 2016.
TUI is taking the 787 for use by four of its carriers: Arkefly, Jetairfly, Thomson Airways and TUI Fly Nordic.
It took delivery of its first 787 in May, a General Electric GEnx-powered example operated by Thomson Airways, and already has four of the type. It says its next two aircraft will join in the coming months and be deployed with Jetairfly and Arkefly.
TUI Travel chief executive Peter Long says: "The feedback we receive from those who fly on these aircraft is exceptional and this order allows us to continue to deliver the best possible customer holiday experience."
The tour group originally ordered 23 Boeing 787s, corresponding to orders placed by operators before the group merged. In 2009 it cancelled 10 of the type, but added 13 purchase rights.
No engine selection has been given for the two newly-ordered aircraft.