Exact methods for the traveling salesman problem with multiple drones

Cavani, S., Iori, M., & Roberti, R. · 2021

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A paper that keeps the fact that moving from one drone to several creates a different exact-model difficulty. It stops the misreading that more aircraft means a city-scale problem has been solved.

The abstract says they treat the traveling salesman problem with multiple drones — one ordinary vehicle and several drones sharing customers — with a compact mixed-integer program, valid inequalities, and a decomposition with branch-and-cut. That exact approach, they write, solves instances of up to twenty-four customers to proven optimality, improving on earlier exact methods for similar problems that reached about ten customers.

Twenty-four is the customer count of their test instances, not a demand forecast. Payload- and wind-dependent energy, pad slots, and regulation remain outside that reach. Do not stage a contest of head-counts against Roberti and Ruthmair's thirty-nine with one drone.