Los Angeles-based charter start-up Quantum Air has agreed to purchase 22 of Bye Aerospace’s electrically powered, fixed-wing, four-seat eFlyer 4 aircraft and four of its two-seat eFlyer 2s. In an agreement announced this week, Quantum Air also committed to buy two examples of another new electric aircraft that Bye Aerospace now has in development.

The two companies have not yet announced a delivery date for the eFlyers, for which Bye Aerospace is now completing the critical design review. It expects to achieve FAA FAR 23 type certification for the eFlyer 2 in 2021, with the eFlyer 4 expected to follow about a year later.

In 2018, Quantum Air reached a provisional agreement with Workhorse to buy an unspecified number of its SureFly multicopter eVTOL aircraft. The status of this deal (valued at $2 million at the time) is unknown, but Workhorse is understood to be trying to sell the program.

Denver-based Bye Aerospace’s founder and CEO George Bye has joined Quantum’s board of advisors. “One of Quantum Air’s goals is to disrupt aviation, providing more accessible, cost-efficient high-speed air transportation solutions—including FAA Part 135 on-demand air taxi travel—to help alleviate the noise and CO₂ emissions challenges that accompany traditional internal combustion aircraft,” he commented.

Separately, Bye Aerospace’s partner Oxis Energy is about to start building proof-of-concept lithium-sulfur batteries that it says will have a significantly better power-to-weight ratio than existing lithium-ion batteries (at 500 Wh/kg vs 250 Wh/kg). Under an agreement announced in July, Oxis and Bye are working together on plans to substitute the lithium-sulfur batteries for existing lithium-ion units in the eFlyer aircraft, with a view to being ready to make the switch from early 2021. UK-based Oxis has already developed lightweight pouches to contain the batteries for integration with the aircraft’s powertrain.

Dr. Mark Crittenden, Oxis Energy’s head of battery development and integration, told AIN that for the first 12 months of the partnership it will be ground testing the proof-of-concept batteries before preparing for flight testing. Oxis has previously done some development work with lithium-sulfur batteries for various unmanned air vehicle programs, including one with Airbus.