International Airlines Group (IAG) announced Thursday it has signed a deal for 18 of Boeing's 787 Dreamliners.The agreement shows a sign of faith in the aircraft which has been grounded since January due to battery problems. IAG will replace some of the existing fleet of Boeing 747-400s for subsidiary British Airways between 2017 and 2012.Its Spanish flag carrier Iberia has also reached a deal with Boeing to secure commercial terms and delivery slots that could lead to an order of 787s.Boeing has said it would have the 787s up and running by mid-April following design changes to the battery system. Flights of the 787 were banned after lithium-ion batteries overheated in two of the aircraft in January.Chief Executive of IAG, Willie Walsh, said new technology engines and improved aerodynamics will lower fuel burn leading to reduced carbon and NOx emissions."British Airways has 24 Boeing 787s on order already and we plan to boost this by a further 18 aircraft by exercising our options," he said."The aircraft offers a step change in fuel burn efficiency versus our existing aircraft with improvements in fuel cost per seat of more than 20%." British Airways' 787s will be powered by Rolls-Royce Trent 1000 engines. The engine order includes a maintenance package with a total care agreement, IAG said.British Airways has 118 wide-bodied longhaul aircraft in its fleet with 42 aircraft ordered while Iberia has 31 wide-bodied longhaul aircraft with six aircraft ordered.RD