When I completed the Foxtrot Interceptor research I immediately went to the workshop to attempt to fabricate it and was of course greeted with this message. Realizing I needed hangar space I immediately built an extra hangar. Upon completion of the hangar I tried to fabricate again and was successful in bringing the project under the Current Projects list, and put 10 technicians on the project. However when I tried to increase the Quantity from "0/1" to "1/1" I was unfortunately greeted with this message again, despite an empty and complete hangar in my base with no vehicles out on missions. The cost has been subtracted from my funds and and I've been given a Completion Time of "3 days 23 hours", but the quantity still reads "0/1". What am I missing here?
edit: Wait nevermind...looks like it's actually building. Turns out I'm an idiot. What does the quantity value do then?