We formulate the strategic interaction between the regulatory airspace governance and the platform competition in the emerging drone food delivery market of Dubai as a two-stage Stackelberg-Nash game. The regulator (Dubai Civil Aviation Authority), as a Stackelberg leader, sets the quota of airspace slots, the licensing fee per delivery, and the safety threshold to maximize social welfare. After observing the regulatory decisions, two competing food delivery platforms, (Keeta Drone and Talabat), simultaneously choose delivery prices and drone fleet investments as Nash competitors, subject to a shared airspace capacity constraint that links their costs through a congestion externality. We obtain a closed-form Subgame Perfect Nash Equilibrium, and reveal five key propositions characterising the (i) airspace Tragedy of the Commons, (ii) optimal licensing fee, (iii) self-reinforcement of Keeta's cost advantage through coopetition, (iv) strategic complementarity of fleet investments, and (v) safety-investment Pareto complementarity. Finally, using a numerical analysis considering Dubai market data, we quantify welfare losses from market asymmetry, and suggest optimal regulatory policies to DCAA.