As threatened, the witches of the morning shift were there to wake Wolfe up promptly at dawn. They had already finished all six of the engines for the cargo plane, and they were ready for Wolfe to come and set up the spells for the main structure of the aircraft.
Once this first setup was done, it would be much easier for them to make the successive aircraft, but everything had to be perfect to get all the parts to line up correctly. Such a large vehicle was a precision bit of engineering, and though they had directly stolen the design after it was tested, they couldn't afford to slack at all in the quality control for their replicas.
Fortunately, they were using strengthening magic, so even if their alloys weren't right, they would still survive the stresses of heavy use. But with the higher ranked witches working on the project, they had a pretty good idea of what they needed out of the metals that they were using.