AerCap (NYSE: AER) and Boeing (NYSE: BA) announced an order for 15 787-9 Dreamliner aircraft, bringing AerCap's total 787 Dreamliner portfolio to approximately 140 airplanes.

The agreement, announced at the Farnborough Airshow in the United Kingdom, includes substitution rights for the larger 787-10 variant, which AerCap said gives it the option to switch to a model offering 50 more seats than the 787-9.

"The addition of these 15 Boeing 787 Dreamliner airplanes to our fleet further strengthens our position as the world's largest owner of 787 jets," said Aengus Kelly, CEO of AerCap. "As demand for modern, fuel-efficient widebody airplanes continues to grow, this transaction enables us to provide our customers with greater access to one of the industry's most versatile and sought-after airplane families."

Stephanie Pope, president and CEO of Boeing Commercial Airplanes, said the continued investment "underscores the airplane's role in enabling long-haul connectivity and superior economics for airlines."

AerCap claims to be the largest lessor of 787 Dreamliner jets and says it was the first lessor to take delivery of the aircraft in 2013. The Dublin-headquartered company serves approximately 300 customers globally.