hollowblade 
"[@royalbardofequestria93":](/images/1623674#comment_8639211
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You got it backwards. The engine design is almost entirely Delta's, something she started even before meeting Jet. Jet just piggy-backed and did barely any work on it. It was the design that was going to get Delta into pony NASA (whatever it's called) until Jet got her pregnant. Also, since Jet has built his entire company off that design, he made sure Delta couldn't legally use it herself or bring it to another company.
You got it backwards. The engine design is almost entirely Delta's, something she started even before meeting Jet. Jet just piggy-backed and did barely any work on it. It was the design that was going to get Delta into pony NASA (whatever it's called) until Jet got her pregnant. Also, since Jet has built his entire company off that design, he made sure Delta couldn't legally use it herself or bring it to another company.