A couple of years ago, UK-based Hybrid Air Vehicles captivated the world when it unveiled the Airlander 10, a lighter-than-air airship designed as an alternative to airplanes and helicopters. Now, according to The Guardian, that first prototype won’t take to the skies again, as the company says that it “does not plan to fly the prototype aircraft again.”

The Airlander 10, nicknamed the “flying bum,” was originally designed by the US Army in 2010 as a reconnaissance and surveillance platform (called the Long Endurance Multi-intelligence Vehicle), one that could remain aloft for weeks at a time. When budget cuts left the project with a questionable future, Hybrid Air Vehicles purchased the prototype and brought it to the UK, with the intent to convert it for the civilian marketplace, carrying cargo and passengers. Made of carbon fiber, kevlar, and mylar, the vehicle is filled with helium and uses diesel engines to take off, steer, and land.

The company received a pair of grants from the UK government and the European Union to help the company test out the vehicle. The airship took its first test flight in 2016, successfully taking off, turning, and landing, but its second test flight wasn’t so successful, as the airship crashed into a field, damaging the cockpit. The vehicle was later repaired and completed several additional test flights through 2017, although it suffered another incident when it broke free of its moorings and deflated in 2017, injuring two people. The vehicle sustained “significant damage” in the incident, and prompted the company to retire the vehicle.

Hybrid Air Vehicles told The Guardian that the prototype has “served its purpose,” and that it provided enough data for them to move forward with a production model. As such, the airship won’t be repaired and returned to service. The company says that it is now focusing on “bringing the first batch of production-standard, type-certified Airlander 10 aircraft into service with customers.” The company also plans a larger version — the Airlander 50 — designed to carry a 50-ton payload.