Rolls said it was planning a second set of static tests, and plans to fit a second version of the engine tested on the back of a superjumbo A-380 for aerial testing. The aircraft maker warned that commercial airliners will rely on conventional engines until 2050 due to the significant design changes in airframes and infrastructure needed. Testing was conducted a low speed, but it was a proof of concept welcomed by Rolls' partner, Easy Jet. That company's CEO said,"We've come to the conclusion that hydrogen is a very exciting proposition for us."
The AE-2100 is generally used in turbo-prop aircraft that run at slower speeds than a jet engine. The energy density required to power a jet aircraft the size of 747 would take one million liters of hydrogen compared to 250,000 liters of jet fuel. Liquid hydrogen fuel must be stored at high pressure and -253℃, necessitating complete re-design of fuel tanks and airframe. Nevertheless, a few companies are pressing ahead with hydrogen as an alternative to fossil fuel. Airbus is working with engine manufacturer CFM International to test hydrogen propulsion. Engineers have come to the tentative conclusion that large electric airliners are impracticable due to the weight of current batteries. Hydrogen provides much more power per kilogram than batteries.