Air TransportAeronautical Engineers Inc. (AEI) has launched a passenger-to-freighter conversion program for the Boeing 737-900ER, targeting US Federal Aviation Administration certification in 2029.
The move follows increasing market interest in narrowbody freighters with greater capacity. AEI has previously converted other 737 models, and now seeks to address operators’ requirements for higher payload and volume.
“This is a strategic move to address the increasing demand for higher-capacity narrowbody freighters,” said Robert T. Convey, AEI Senior Vice President of Sales and Marketing. “With the global e-commerce and express markets continuing to grow, the B737-900ERSF will provide operators with the right blend of payload, volume, and economics.”

The converted 737-900ERSF will offer 207 cubic meters of cargo space, accommodate 12 standard cargo pallets, and support a maximum payload of 26,173 kg. Modifications will include floor reinforcement, a cabin barrier installation, and a cargo loading system supplied by Ancra Aircraft.
AEI expects to secure a supplemental type certificate from the FAA in 2029, with subsequent approvals sought from European and Chinese regulators.
The Boeing 737-900ER was introduced in July 2005, first flew in September 2006, and was delivered to its launch customer, Lion Air, in April 2007.
Approximately 475 Boeing 737-900ERs remain in active service worldwide. Boeing delivered a total of 505 737-900ER aircraft.