Pessimistic with direction of academia-industry project
My answer is rather a statement about what not to do rather what to do: 

Do not do a PhD in a field you are not interested in. And do not choose a field of research for your degree just because of convenience (offer/opportunity). I cannot emphasise that enough. 

In addition, switching topics drastically after a PhD is very difficult. It is possible, but I have seen it rarely succeed. 

Usually, people start with a related topic and then drift away in the direction they are interested in. However, drifting from ATC to Topology/QM does not look obvious; Quantum airplanes? Topological path planning? Braid groups for flight patterns? Perhaps...