Celera 500L Design By Otto Aviation Surfaces Otto Aviation revealed more about a new design this week that it wants to bring to market by 2025. The blimp-style aircraft called the Celera 500L is a run by a pusher-prop connected to 500-hp Red A03 diesel engine. There is a prototype doing tests as well which to date is said to have successfully completed 31 flights. The aircraft will carry six passengers in a stand-up cabin and is capable -on paper- of flying up to 4,500 miles. It also is touted to have a top-cruise speed of 450 mph and an economy of 18 to 25 miles per gallon.